____________________________IMPORTANT_NOTICE____________________________ The ownership of a signal descrambler does NOT give the owner the right to decode or view any scrambled signals without authorization from the proper company or individual. Use of such a device without permission may be in violation of state and/or federal laws. The information contained herein is intended to serve as a technical aid to those person seeking information on various scrambling techniques. No liability by myself or my employer is assumed for the (mis)use of this information. ________________________________________________________________________ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * _________________________Scrambling_Technologies________________________ ................No Scrambling (Traps/Addressable Taps).................. A cable system may not be scrambled at all. Some older systems (and many apartment complexes) use "traps" or "filters" which actually REMOVE the signals you aren't paying for from your cable. (These are negative traps because they remove the WHOLE signal.) These systems are relatively secure because the traps are often located in locked boxes, and once a service technician finds out they're missing or have been tampered with (by pushing a pin through a coax trap it to change its frequency, for example), it's a pretty solid piece of evidence for prosecution. Another method is where the head-end ADDS an extraneous signal about 2.5 MHz above the normal visual carrier which causes a tuner to think its receiving a very strong signal--the tuner then adjust the automatic gain control and buries the real signal. If you pay for the service, the cable company adds a "positive trap" which then REMOVES the extraneous injected signal so it becomes viewable. (This system is very easy to circumvent by building your own notch filter, so it is not very commonly used.) Advantages to a cable system with this technology is that you don't need a cable box--all your cable-ready TVs, VCRs, etc. will all work beautifully. The disadvantage is that pay-per-view events are not possible, and that every time someone requests a change in service, a technician has to be dispatched to add/remove the traps. An article for building a tunable notch filter to block data streams sent just above the FM band was in the April 1992 issue of Radio-Electronics (pp. 37-39). Notch filters (as well as kits for them) for other frequencies are frequently advertised in Nuts & Volts magazines as "beep" filters and the like. Becoming more and more popular, not only because of the Cable Act of 1992 but also in an effort to stop "pirates" are addressable taps. Many cable companies will be moving to this technology in the near future, (which they call "interdiction"). These are devices located at the pole, where your individual cable feed is tapped from the head-end. Similar to addressable converters, they each have a unique ID number and can be turned on/off by a computer at the head-end. Any stations which you are not paying for are filtered out by electronicly switchable traps in the units. (Including the whole signal if you haven't paid your bill or had the service disconnected.) {Several patents have already been issued for various methods of making SURE you don't see a channel you don't pay for.} Again, these almost GUARANTEE an end to piracy and don't have any of the disadvantages of the manual traps. Plus, they provide a superior signal to those customers paying for service because they no longer need complicated cable boxes or A/B switches -- and they can finally use all of the "cable-ready" capabilites of the VCR, TV, etc. About the only known attack on this type of system is to splice into a neighbors cable, which again provides plenty of physical evidence for prosecution. ...............................Sine-Wave................................ Early Oak (and some very early Pioneer boxes) employed a sine-wave sync suppresion system. In this system, the picture would remain vertically stable, but wiggling black bars with white on either side would run down the center of the screen. The lines were caused by a 15,750 Hz sine-wave being injected with the original signal, causing the sync separator in the TV to be unable to detect and separate the sync pulses. Later, Oak came out with a "Vari-Sync" model, which also removed a 31,500 Hz sine-wave added to the signal. Oak was one of the first to use extra signals ("tags") as a counter-measure for pirate boxes -- in the normal mode, a short burst of a 100 KHz sine-wave (the tag signal) would be sent during the VBI, along with the AM sine-wave reference on the audio carrier and scrambled video. They would then put the AM sine-wave reference signal onto the audio carrier, leave the video alone, and NOT send the tag. Any box which simply looked for the AM sine-wave reference would effectively scramble the video by adding a sine-wave to the unscrambled video! Real decoders looked for the tag signal and still worked correctly. Other combinations of tag/no tag, scrambled/unscrambled video were also possible. .....................6 dB In-Band Sync Suppression...................... Early Jerrold boxes used in-band gated sync suppression. The horizontal blanking interval was suppressed by 6 dB. A 15.734, 31.468 or 94.404 KHz reference signal (conveniently all even multiples of the horizontal sync frequency) was modulated on the sound carrier of the signal, and used to reconstruct the sync pulse. An article in February 1984 issue of Radio-Electronics explains this somewhat-old technique. Converters which have been known to use this system include the Scientific-Atlanta 8500-321/421, a number of Jerrold systems [see numbering chart], Jerrold SB-#, SB-#-200, SB-#A, RCA KSR53DA, Sylvania 4040 and Magnavox Magna 6400. ...................Tri-mode In-Band Sync Suppression.................... A modification to the 6dB sync suppresion system, dubbed "tri-mode", allows for 0, 6 and 10 dB suppression of the horizontal sync pulse. The three sync levels can be varied at random (as fast as once per field), and the data necessary to decode the signal is contained in unused lines during the VBI (along with other information in the cable data stream.) See the February 1987 issue of Radio-Electronics for a good article (both theory and schematics) on the tri-mode system. Converters which have been known to use this system include a number of Jerrold systems [see numbering chart], Jerrold SBD-#A, SBD-#DIC, Jerrold Starcom VI (DP5/DPV models), Regency, Scientific- Atlanta 8550-321 {anyone know any others for sure?} and early Pioneer systems {anyone know for sure which ones?}. .......................Out-Band Sync Suppression........................ Out-band gated sync systems also exist, such as in early Hamlin converters. In this system, the reference signal is located on an unused channel, usually towards the higher end (channels in the 40's and 50's are common, but never in the low 30's due to potential false signalling.) The signal is comprised of only sync pulse information without any video. Tuning in such a channel will show nothing but a white screen and will usually have no audio. .............................SSAVI / ZTAC............................... SSAVI is an acronym for Synchronization Suppression and Active Video Inversion and is most commonly found on Zenith converters. ZTAC is an acronym for Zenith Tiered Addressable Converter. Besides suppressing sync pulses in gated-sync fashion, video inversion is used to yield four scrambling modes (suppressed sync, normal video; suppressed sync, inverted video; normal sync, inverted video; and normal sync, normal video). The horizontal sync pulses of an SSAVI signal can be absent completely, at the wrong level, or even present, and can be varied on a field-by-field basis. Any decoder for an SSAVI (or similar) system has to be able to separate a video line into its two basic components-- the control and picture signals. In SSAVI, the horizontal sync is never inverted, even if the picture is. So a method of inverting the picture without inverting the control section is necesary. This is complicated by the fact that almost every line in an SSAVI signal has no horizontal sync information, making it difficult to perform the separation (since the usual reference point--the horizontal sync pulse--is gone). In the older suppressed-sync system, the sync pulse could be recovered from the gating signal buried in the audio subcarrier, but SSAVI is "pilotless". The key to this system relies on the strict timings imposed by the NTSC standard--if you can locate one part of the signal accurately, you can determine where everything else should be mathematically. Since the cable company is sending a digital data stream---the security and access-rights--during the VBI of the signal, the VBI makes a great place to find a known point in the signal. Obviously if the electronics in the cable box can locate this information, so can electronics outside the cable box! :-) The only constant in the SSAVI system are the horizontal sync pulses during the VBI (the first 26 lines of video), which are sent "in the clear". The pulses from the VBI can be used as a reference for a phase-locked loop (PLL) and used to supply the missing pulses for the rest of the video frame. With 20 or so reliable pulses at the beginning of each frame, you can accurately generate the missing 240 or so pulses. Of the 26 lines in the VBI, lines zero through nine are left alone by request of the FCC, lines 10 to 13 are commonly used to transmit a digital data stream, line 21 contains closed-caption information, while other lines are used for a variety of "stuff" depending on the cable system and the channel you're watching. When you tune to a scrambled channel with a cable box, logic circuits in the unit count the video lines, read the transmitted data stream, and compare the transmitted data with the information stored in the box. If the box is authorized to receive the signal with that particular data stream, the decoder is enabled and the scrambled signal becomes viewable. If not, the signal is passed through without being decoded, or more commonly, a "barker" channel (whose channel number is sent via the data stream) is automatically tuned instead. This prevents people from using the unit as a tuner for "add-on descramblers" often advertised in the back of electronics magazines. In the SSAVI system, the video can be sent with either normal or inverted picture information. The descrambler needs a way to determine whether to invert the video or not. Originally this information could be found on line 20, but has since moved around a lot as the popularity (and knowledge) of the system increased. In any event, the last half of the line would tell the decoder whether to invert the picture or not. If the rest of the field was not inverted, the last half of the line would be black. If the video in the rest of the frame was inverted, the last half of the line would be white. The Drawing Board column of Radio-Electronics starting in August '92 and going through May '93 described the system and provided several circuits for use on an SSAVI system. Note that audio in the system can be "scrambled" - usually by burying it on a subcarrier that's related mathematically to the IF component of the signal. Addressable data for Zentih systems is sent in the VBI, lines 10-13, with 26 bits of data per line. ..............................Tocom systems............................. The Tocom system is similar to the Zenith system since it provides three levels of addressable baseband scrambling: partial video inversion, random dynamic sync suppression and random dynamic video inversion. Data necessary to recover the signal is encrypted and sent during lines 17 and 18 of the VBI (along with head-end supplied teletext data for on-screen display). The control signal contains 92 bits, and is a 53 ms burst sent just after the color burst. Up to 32 tiers of scrambling can be controlled from the head-end. Audio is not scrambled. ..........................New Pioneer systems........................... The newer 6000-series converters from Pioneer supposedly offer one of the most secure CATV scrambling technologies from a "major" CATV equipment supplier. From the very limited information available on the system, it appears that false keys, pseudo-keys and both in-band and out-band signals are used in various combinations for a secure system. From U.S. patent abstract #5,113,441 which was issued to Pioneer in May '92 (and may or may not be used in the 6000-series converters, but could be), "An audio signal is used on which a key signal containing compression information and informaton concerning the position of a vertical blanking interval is superimposed on a portion of the audio signal corresponding to a horizontal blanking interval. In addition, a pseudo-key signal is superimposed...so that the vertical blanking interval cannot be detected through the detection of the audio signal... Descrambling can be performed by detecting the vertical blanking interval based on the information...in the key signal, and decoding the information for the position which is transmitted in the form of out-band data. Compression information can then be extracted from the key signal based on the detected vertical blanking interval, and an expansion signal for expanding the signal in the horizontal and vertical blanking periods can be generated." {If anyone has any better information on the 6000-series scrambling technique, please send mail!} Note that Pioneer boxes are "booby-trapped" and opening the unit will release a spring-mechanism which positively indicates access was gained to the interior (and sends a signal to the head-end on a two-way system, and may disable the box completely.) {See U.S. patent #4,149,158 for details.} The unit cannot be reset without a special device. Pioneer systems transmit their addressing data on 110.0 MHz. .....................New Scientific-Atlanta Systems..................... Some of the early S-A boxes used 6 dB only sync suppression (some of the 8500 models), and some of the 8550 boxes are tri-mode systems. The three digit number after the model (such as 321) is a code which indicates the make of the descrambler in the unit. Apparently some of the newer S-A boxes use a technique called "dropfield". {If anyone has more information on any of the 85xx-series or the 8600^x boxes, or an explanation of "dropfield", send mail...} Scientific-Atlanta systems transmit their addressing data on 106.2 or 108.2 MHz. ............................Oak "Sigma" Systems......................... This a secure system which replaces the horizontal sync of each line of video with a three-byte digital word. Video is switched from inverted to non-inverted between scene changes, and the colorburst frequency is shifted "up". This is a standard "suppressed" sync video scrambling method and is relatively simple to defeat with the appropriate circuitry. HOWEVER, the three-byte digital word in the area where the sync normally is contains audio and sync information. The first two bytes contain a digitized versions of the audio, the third byte contains sync information (and perhaps addressing data?) The two bytes of digitized audio are encrypted; a separate carrier signal contains the decryption keys for the digital audio datastream. ............................Jerrold Baseband............................ No information on techniques used by Jerrold "baseband" converters. {If anyone has information on other Jerrold scrambling methods other than those mentioned above, send mail.} ...............................Chameleon................................ The research and development division of Fundy Cable Ltd., NCA Microelectronics, has a systemd dubbed "Chameleon". They claim it is a cost-effective solution that prevents pay TV theft by digitally encrypting the video timing information of sync suppression systems. The company claims the technology has been proven to be effective against pirate and tampered boxes. Supposedly, existing decoders can be upgraded to Chameleon technology with a low-cost add-in circuit, and that the card's sealed custom IC, developed by NCA, is copy-proof. ..............................VideoCipher............................... The VideoCipher system is now owned by General Instrument and is used primarily for satellite signals at this time. VideoCipher I is the "commercial" version which uses DES (Data Encryption Standard)-encrypted audio AND video. A VCI descrambler is not available for "home" owners. VideoCipher II is the now-obsolete system which used a relatively simple video encryption method with DES-encrypted audio. (Specifically, the audio is 15 bit PCM, sampled at ~44.1 KHz. It is mu-law companded to 10 bits before transmission.) This has recently been replaced by the VideoCipher II+, which has been incorporated as the 'default' encryption method used by VideoCipher IIRS (a smart-card based, upgradeable system). Supposedly, coded data relating to the digitized, encrypted audio is sent in the area normally occupied by the horizontal sync pulse in the VCII system. (The Oak Sigma CATV system uses a similar technology.) Several methods existed for pirating the VCII based system, and some SUPPOSEDLY exist for the new VCII+ format, although this has never been verified. See the rec.video.satellite FAQ list for more information. .........................DigiCable/DigiCipher........................... DigiCipher is an "upcoming" technology being developed by General Instrument for use in both NTSC and HDTV environments. The DigiCipher format is for use on satellites, and the DigiCable variation will address CATV needs. It provides compression algorithms with forward error correction modulation techniques to allow up to 10 "entertainment quality" NTSC channels in the space normally occupied by one channel. It provides true video encryption (as opposed to the VCII-series which only DES encrypts the audio). In a Multiple Channel Per Carrier (MCPC) application, the data rate is ~27 MB/second via offset QPSK modulation. Audio is CD-quality through Dolby AC-2 technology, allowing up to four audio channels per video channel. The system uses renewable security cards (like the VCIIRS), has 256 bits of "tier" information, copy protection capability to prevent events from being recorded, commercial insertion capability for CATV companies, and more. The multichannel NTSC satellite version of DigiCipher started testing in July of 1992, and went into production several months later. ................................B-MAC................................... MAC is an acronym for Mixed Analog Components. It refers to placing TV sound into the horizontal-blanking interval, and then separating the color and luminance portions of the picture signal for periods of 20 to 40 microseconds each. In the process, luminance and chrominance are compressed during transmission and expanded during reception, enlarging their bandwidths considerably. Transmitted as FM, this system, when used in satellite transmission, provides considerably better TV definition and resoluton. Its present parameters are within the existing NTSC format, but is mostly used in Europe at this time. {Does anyone know if the D2-MAC system is just a variation of this, or is it completely different? What's new in the D2-MAC system?} ________________________Miscellaneous_Information_______________________ .........................Two-Piece vs. One-Piece........................ There are both advantages and disadvantages to the one-piece and two-piece descramblers often advertised in the back of electronics magazines. The "one-piece units" are real cable converters, just like you'd get if you rented one from the cable company. It has the advantages of "real" descrambling circuitry and the ability to "fit-in" well when neighbors come over (avoids those "my box doesn't look like that...or get all these channels!" conversations :-) A disadvantage is that if you move or the cable company installs new hardware, you may now have a worthless box -- most one-piece units only work on the specific system they were designed for. Another disadvantage is that if the box has not been modified, it can be very easy for the head-end to disable the unit completely. (See Market Codes & Bullets, below.) A "two-piece unit" ("combo") usually consists of an any-brand cable TV tuner with a third-party "descrambler" (often referred to as a "pan") which is designed to work with a specific scrambling technology. The descrambler typically connects to the channel 3 output of the tuner, and has a channel 3 output which connects to your TV. (Although some tuners have a "decoder loop" for such devices.) They have the advantage that if you move or your system is upgraded, you can try to purchase a new descrambler -- which is much cheaper than a whole new set-up. You also can select the cable TV tuner with the features you want (remote, volume control, parental lockout, baseband video output, etc.) Two-piece units typically cannot be disabled by the data stream on your cable. (Note however that there ARE add-on "pans" manufactured by the same companies who make the one-piece units that DO pay attention to the data stream and can be disabled similarly!) The main disadvantage is that a third-party descrambler MAY not provide as high of quality descrambling as "the real thing", and it may arrouse "suspicion" if someone notices your "cable thing" is different from theirs. ........................Jerrold Numbering System........................ To decode older Jerrold converters, the following chart may be helpful. (Note that some spaces may be blank.) {Send along any additions or other numbering systems you know of!} __ __ __ __ - __ __ __ | | | | | | | | | | | | | |___ T = two-way capability, C = PROM programmable | | | | | | | | | | | |______ DI = Inband decoder, DO = Outband decoder, | | | | | PC = Single pay channel, A = Addressable | | | | | | | | | |_________ Output channel number (3 very common) | | | | | | | |______________ D or I = tri-mode system, N = parental lockout | | | feature (6 dB-only systems are "blank" here) | | | | | |_________________ M = mid-band only, X = thru 400 MHz, | | Z = thru 450 MHz, BB = baseband | | | |____________________ S = Set-top, R = Remote | |_______________________ D = Digital tuning, J = Analog tuning Also note that some Jerrold converters (particularly the DP5 series and maybe others) have a tamper-switch, and that opening the box will clear the contents of a RAM chip in the converter. This may or may not be corrected by letting the unit get "refreshed" by the head-end data stream. Most Jerrold systems transmit their addressing data near 97.5, 106.5 or 108.5 MHz. The datastream is Manchester encoded FSK, with approximately a 14kHz clock. ................Scientific-Atlanta Suppressed Sync Boxes................ Model 8600 - _ _ _ _ | | | | | | | |___ Impulse PPV Return: N=none, T=telephone, R=RF | | |_____ Dual cable option: N=none, D=dual cable | |_______ Descrambler type: S=SA standard, K=oak |_________ Channel: S=selectable channel 3/4 The 8600 has 240 character on-screen display, multimode scrambling, 8 event 14 day timer, and is "expandable"... Model 859_ - 7 _ 7 _ | | | | | |__ Dual cable option: D=dual cable | |______ Descrambler: 5=SA scrambling+video inversion, | 7=5+Oak |____________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV The 8590s feature volume control, multimode scrambling, 8 event 14 day timer... Model 858_ - _ 3 _ - _ | | | |__ Dual cable option: D=dual cable | | |______ Data carrier: 6=106.2 MHz, 8=108.2 MHz | |__________ Channel: 3=channel 3, 4=channel 4 |______________ 0=No Impulse PPV, 5=Telephone IPPV, 7=RF IPPV The 8580s use dynamic sync suppression, 8 event 14 day timer, and built-in pre-amp. The 8570 is similar to the 8580. Model 8550 - _ _ _ | | |__ 1=108.2 MHz data stream | |____ Jerrold, dropfield, SA descrambling |______ Channel: 3=channel 3 The 8550 is not a current model; it can be replaced with an 8580-321. Non-addressable products include the 8511, 8536, and 8540. {If anyone has more details/corrections, please send them along.} .............................Market Codes............................... Note that almost every addressable decoder in use today has a unique "serial number" programmed into the unit -- either in a PROM, non-volatile RAM, EAROM, etc. This allows the head-end to send commands specifically to a certain unit (to authorize a pay-per-view events, for example.) Part of this "serial number" is what is commonly called a "market code", which can be used to uniquely identify a certain cable company. This prevents an addressable decoder destined for use in Chicago from being used in Houston. In most cases, when a box receives a signal with a different market code, it will enter an "error mode" and become unusable. This is just a friendly little note to anyone who might consider purchasing a unit from the back of a magazine -- if the unit has not been "modified" in any way to prevent such behavior, you could end up with an expensive paper weight... (see next section) .............................Test Chips................................. So-called "test chips" are used to place single-piece converters (that is, units with both a tuner and a descrambler) into full service. There are a number of ways to accomplish this, but in some cases, the serial number/market code for the unit is set to a known "universal" case or, better yet, the comparison checks to determine which channels to enable/disable are bypassed by replacing an IC in the unit. Hence, the "descrambler" will always be active, no matter what. This latter type of chip is superior because it cannot be disabled and is said to be "bullet proof", even if the cable company finds out about a "universal" serial number. (When the cable company finds out about a universal serial number, it is easy for them to disable the converter with a variation on the "bullet" described below.) ................................Cubes................................... Another type of "test device" has been advertised in magazines such as Electronics Now (formerly Radio-Electronics) and Nuts & Volts. It's called a "cube" and it SIMULATES the addressing data signal for a cable box, most commonly for those from Pioneer and Jerrold (the Zenith data stream is sent in the VBI, making this apporach more difficult). You plug the cable into one side, where it filters out the real data signal, and out the other side comes a normal signal, but with a new data stream. (There are also "wireless" cubes which you just periodically set near your box with the cable disconnected to "refresh" it.) This new data signal tells whatever boxes the cube addresses to go into "full-service" mode (including any cable company-provided boxes). Sometimes it is a non-destructive signal, and if the the "cube" is removed from the line, the real data signal gets to the electronics inside and the converter goes back to normal "non-test" mode. Note that sometimes it IS destructive: there are some cubes that re-program the electronic serial number in a converter to a new value. This type has the advantage that it will work with any converter the cube was designed to test (but changes the serial number to some "preset" value). The "non-destructive" versions of a cube usually require that you provide the serial number from the converter you're interested in "testing". That way a custom IC can be programmed to address that converter with the necessary data. (Otherwise the converter would ignore the information, since the serial number the cube was sending and the one in converter wouldn't match.) ...............................Bullets.................................. First and foremost, THE "BULLET" IS NOTHING MORE THAN THE NORMAL CABLE DATA STREAM WITH THE APPROPRIATE "CODE" TO DISABLE A CONVERTER WHICH HAS NOT BEEN ACKNOWLEDGED BY THE CABLE COMPANY. For instance, the head end could send a code to all converters which says "unless you've been told otherwise in the last 12 hours, shut down." All legitimate boxes were individually sent a code to ignore this shut down code, but the pirate decoders didn't get such a code because the cable company doesn't have their serial number. So they shut down when the see the "bullet" code. The "bullet" is NOT a harmful high-voltage signal or something as the cable companies would like you to believe -- if it was, it would damage anyone with a cable-ready TV or VCR connected to the cable (not something the cable company wants to deal with!) The only way to get "caught" by such a signal is to contact the cable company and tell them your illegal descrambler just quit working for some reason. :-) Not a smart thing to do, but you'd be surprised, especially if it's someone else in the house who calls, like a spouse, child, babysitter, etc. While we're on the subject, it's also not a good idea to have cable service personnel come into your residence and find an unauthorized decoder... .............Time Domain Reflectometry / Leak Detection................. The cable company can use a technique called "Time Domain Reflectometry" (TDR) to try and determine how many devices are connected to your cable. In simple terms, a tiny, short test signal is sent into your residence and the time domain reflectometer determines the number of connections by the various "echoes" returned down the cable (since each device is at a different point along the cable, they can be counted.) Each splitter, filter, etc. will affect this count. A simple way to avoid being "probed" is to install an amplifier just inside your premises before any connections. This isolates the other side of the cable from the outside, and a TDR will only show one connection (the amplifier). The cable company also has various ways of detecting signal "leaks" in their cable. The FCC REQUIRES them to allow only so much signal to be radiated from their cables. You may see a suspicious looking van driving around your neighborhood with odd-looking antennas on the roof. These are connected inside to field strength meters which help locate where the leaks are coming from so they can be fixed (to prevent a fine from the FCC!) If you've tampered with a connection at the pole (say, to hook up a cable that had been disconnected) and didn't do a good job, chances are the connection will "leak" and be easily found by such a device. This can also happen INSIDE your residence if you use cheap splitters/amplifiers or have poorly-shielded connections. The cable company will ask to come inside, and bring with them a portable field strength meter to help them locate the problem. Often they will totally remove anything causing the leak, and may go further (e.g., legal action) if they feel you're in violation of your contract with them (which you agree to by paying your bill.) Obviously it's a bad idea to let cable service personnel into your house if you ARE doing something you shouldn't (which you shouldn't be in the first place), but if you DON'T let them in (as is your right), it will definitely arouse suspicion. Eventually you will have to let them in to fix the "leak", or they will disconnect your cable to stop the leak altogether. (After all, it's a service, not a right, to receive cable!) ...................Some Common Ways Pirates Get Caught.................. There are many ways for a "pirate" to get caught. Since stealing cable is illegal in the U.S., you can be fined and sent to jail for theft of service. Cable companies claim to lose millions of dollars in revenue every year because of pirates, so they are serious in their pursuit of ridding them from their system. . a pirate will often show-off the fact they can get every channel to their friends. Pretty soon lots of people know about it, and then the cable company offers a "Turn In A Pirate And Get $50" program. A "friend" needs the money and turns the pirate in... . a pirate (or more likely, unsuspecting housemate of a pirate who knows nothing about whats going on) calls the cable company to report a problem with the equipment or signal. The cable company makes a service call and finds gray-market equipment connected to the cable... . during a pay-per-view event such as a fight, the cable company offers a free T-shirt to all viewers. Little does the pirate know that just before that message appeared on the screen, legitimate viewer's boxes were told to switch to another channel WHILE STILL DISPLAYING THE ORIGINAL CHANNEL NUMBER (yes, cable boxes can do this.) So now the legitimate subscriber continues to see the "original" signal (without the T-shirt offer), while the pirate gets an 800 number plastered on the screen. The pirate calls, and the cable company gets a list of all potential pirates... . the cable company temporarily broadcasts some soft-core pornography onto what is supposed to be The Disney Channel (and vice-versa). They simultaneously reprogram subscriber converters to re-map the channels correctly, so the change is transparent to all but non-company converters. Those who call to complain about the "non-Disney" entertainment (or cartoons on the Playboy channel :-) are more than likely to have gray-market decoders... . a big cable descrambler business gets busted. The authorities confiscate their UPS shipping records and now have a list of "customers" who most likely ordered descramblers for illegitimate use... And this is only the beginning. Unconfirmed reports of the cable company driving around with special equipment allowing them to determine what you're watching on your TV (like HBO, which you don't pay for) have also been mentioned. Of course, the best thing to do is simply PAY FOR WHAT YOU WATCH! Then you don't have to worry about the possibility of a prison term, criminal record, hefty fine, etc. ........................The Universal Descrambler....................... In May of 1990, Radio-Electronics magazine published an article on building a "universal descrambler" for decoding scrambled TV signals. There has been much talk on the net about the device, and many have found it to be lacking in a number of respects. Several modifications, hoping to fix some of the problems have also been posted, with limited success. The Universal Descrambler relies on the presence of the colorburst for its reference signal. In a normal line of NTSC video, the colorburst is 8 to 11 cycles of a 3.579545 MHz clock (that comes out to 2.31 microseconds) which follows the 4.71 microsecond horizontal sync during the horizontal blanking interval. {Whew!} Since a large number of scrambling systems depend on messing with the horizontal sync pulse to scramble the picture, the Universal Descrambler attempts to use the colorburst signal to help it replace the tainted sync pulse. Unfortunately, random video inversion is still a problem, as are color shifts which occur from distorted or clamped colorburst signals, etc. Most people have not had very good results from the system, even after incorporating some modifications. ________________________Glossary_of_Related_Terms_______________________ {Suggestions or contributions to the glossary are welcome!} CATV: Acronym for Community Antenna TeleVision. Originally cable TV came about as a way to avoid having everyone in a community have to spend a lot of money on a fancy antenna just to get good TV reception. Really all you need is one very good antenna and then just feed the output to everyone. It was called Community Antenna Television (CATV). Of course, it has grown quite a bit since then and everyone now just calls it cable TV. The old acronym still sort-of works. Converter: A device, sometimes issued by the cable company, to "convert" many TV channels to one specific channel (usually channel 3). Used early-on when VHF & UHF channels were on different dials (and before remote controls) to provide "convenience" to cable customers. Now mostly considered a nuisance, thanks to the advent of cable-ready video equipment, they are mainly used as descramblers. An "addresable" converter is one that has a unique serial number and can be told (individually) by the head-end to act in a certain manner (such as enabling channel x, but not channel y). Addressable converters nearly always contain descramblers for decoding premium services subscribed to by the customer. Colorburst: Approximately 8 to 10 cycles of a 3.579545 MHz clock sent during the HBI. This signal is used as a reference to determine both hue and saturation of the colors. A separate colorburst signal is sent for each line of video, and are all exactly in phase (to prevent color shifts). Control Signal: The first 11.1 microseconds of a line of NTSC video. The signal area from 0 to 0.3 volts (-40 to 0 IRE units) is reserved for control signals, the rest for picture information. If the signal is at 0.3 volts (or 0 IRE) the picture will be black. See IRE Units; Set-up Level. Field: One half of a full video frame. The first field contains the odd numbered lines, the second field contains the even numbered lines. Each field takes 1/60th of a second to transmit. Note that both fields contain a complete vertical-blanking interval and they both (should) have the same information during that interval. Since the NTSC standard is 525 lines, each field contains 262.5 lines--therefore it's the half-line that allows the two fields of a frame to be distinguished from one another. See Frame; Line. Frame: An NTSC video signal which contains both fields. A frame lasts 1/30th of a second. See Field; Line. Head-end: The main cable distribution facility where your CATV signal originates from. (Easily identifed by several large satellite dishes, some smaller ones, and usually an antenna tower.) HBI: Acronym for Horizontal Blanking Interval. The first 11.1 microseconds of a line of video. It contains the front porch, the 4.71 microsecond horizontal sync pulse, the 2.31 microseconds of colorburst, and the back porch. The horizontal sync pulse directs the beam back to left side of the screen. Almost every scrambling method in use today mutataes this part of the signal in some way to prevent unauthorized viewing. See Colorburst. Interlace: Term used to describe the dual-field approach used in the NTSC standard. By drawing every other line, screen flicker is increased--but if all the lines were painted sequentially, the top would begin to fade before the screen was completely "painted". (Computer monitors, which do "paint" from top to bottom, do not have the problem due to higher refresh rates.) IPPV: Impulse Pay-Per-View. A method whereby a viewer can order a pay-per-view event "on impulse" by just pushing an "Order" (or similar) button on a remote control or cable converter keypad. A customer's purchases are sent back to the head-end via a standard telephone connection (the converter dials into the cable co. computer and uploads the data) or via radio frequency (RF) if the cable supports two-way communication (most don't). A pre-set maximum number of events can be ordered before the box requires the data to be sent to the head-end for billing purposes. IRE Units: IRE is an acronym for Institure of Radio Engineers. The NTSC standard calls for a peak-to-peak signal voltage of 1 volt. Instead of referring to the video level in volts, IRE units are used instead. The IRE scale divides the 1- volt range into 140 parts, with zero-IRE corresponding to about 0.3V. The full scale goes from -40 IRE to +100 IRE. This is convenient scale to make a distinction between control signals (< 0 IRE) and picture signals (> 0 IRE). See Control Signal. Line: A video signal is a series of repeated horizontal lines, consisting of control and picture information. The color NTSC standard allows a total time of 63.56 microseconds for each line, and each frame is composed of 525 lines of video information. The first 11.1 microseconds make up the horizontal blanking interval, or control signal, the following 52.46 microseconds make up the picture signal. See HBI; VBI. NTSC: Acronym for National Television Standards Committee (or Never The Same Color, if you prefer :-) Picture Signal: The 52.46 microseconds of signal following the control signal. Information in this area is between 0 and 100 IRE units. See IRE Units. PPV: Acronym for Pay-Per-View. A revenue-enhancing system where customer's pay to watch a movie or event on a "per view" basis. Cusomers usually place a phone call to a special number and order the event of their choice; some systems provide Impulse PPV. The presence of a PPV movie channel or your system guarantees you have addressable converters. See IPPV. Set-up Level: Picture information technically has slightly less than 100 IRE units available. That's because picture information starts at 7.5 IRE units rather than at 0 IRE units. The area from 0 to 7.5 IRE units are reserved for what is commonly called the "set-up level". Having a small buffer area between the control signal information and the picture information is a "fudge factor" to compensate for the fact that real-life things that don't always work as nicely as they do on paper. :-) See IRE Units. VBI: Acronym for Vertical-Blanking Interval. The first 26 lines of an NTSC video signal. This signal is used to direct the beam back to the upper-left corner of the screen to start the next frame. In order for the horizontal sync to continue operating, the vertical pulse is serrated into small segments which keep the horizontal circuits active. Both actions can then take place simultaneously. The VBI is the most common place for "extra" information to be sent, such as various test signals, and in some cable systems, a data stream. _______________________Television_Frequency_Chart_______________________ The following chart lists frequency information for the "standard" carrier sets. HRC (Harmonically Related Carrier) and IRC encoding methods are slightly different. {Can anyone provide specifics on the different frequency formats? Ed.} Center Video Color Sound Osc. Channel Band Freq. Carrier Carrier Carrier Freq. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ VHF-Low Band TVIF 40-46 43 41.25 44.83 47.75 2 54-60 57 55.25 58.83 59.75 101 3 60-66 63 61.25 64.83 65.75 107 4 66-72 69 67.25 70.83 71.75 113 5 76-82 79 77.25 80.83 81.75 123 6 82-88 85 83.25 86.83 87.75 129 ----------------------------------------------------------- FM (Pseudo) FM-1 88-94 91 89.25 92.83 93.75 FM-2 94-100 97 95.25 98.83 99.75 FM-3 100-106 103 101.25 104.83 105.75 ----------------------------------------------------------- VHF-Mid Band (CATV) A2-(00) 108-114 111 109.25 112.83 113.75 155 A1-(01) 114-120 117 115.25 118.83 119.75 161 A-(14) 120-126 123 121.25 124.83 125.75 167 B-(15) 126-132 129 127.25 130.83 131.75 173 C-(16) 132-138 135 133.25 136.83 137.75 179 D-(17) 138-144 141 139.25 142.83 143.75 185 E-(18) 144-150 147 145.25 148.83 149.75 191 F-(19) 150-156 153 151.25 154.83 155.75 197 G-(20) 156-162 159 157.25 160.83 161.75 203 H-(21) 162-168 165 163.25 166.83 167.75 209 I-(22) 168-174 171 169.25 172.83 173.75 215 ----------------------------------------------------------- VHF-High Band 7 174-180 177 175.25 178.83 179.75 221 8 180-186 183 181.25 184.83 185.75 227 9 186-192 189 187.25 190.83 191.75 233 10 192-198 195 193.25 196.83 197.75 239 11 198-204 201 199.25 202.83 203.75 245 12 204-210 207 205.25 208.83 209.75 251 13 210-216 213 211.25 214.83 215.75 257 ----------------------------------------------------------- VHF-Super Band (CATV) J-(23) 216-222 219 217.25 220.83 221.75 263 K-(24) 222-228 225 223.25 226.83 227.75 269 L-(25) 228-234 231 229.25 232.83 233.75 275 M-(26) 234-240 237 235.25 238.83 239.75 281 N-(27) 240-246 243 241.25 244.83 245.75 287 O-(28) 246-252 249 247.25 250.83 251.75 293 P-(29) 252-258 255 253.25 256.83 257.75 299 Q-(30) 258-264 261 259.25 262.83 263.75 305 R-(31) 264-270 267 265.25 268.83 269.75 311 S-(32) 270-276 273 271.25 274.83 275.75 317 T-(33) 276-282 279 277.25 280.83 281.75 323 U-(34) 282-288 285 283.25 286.83 287.75 329 V-(35) 288-294 291 289.25 292.83 293.75 335 W-(36) 294-300 297 295.25 298.83 299.75 341 ----------------------------------------------------------- VHF-Hyper Band (CATV) AA-(37) 300-306 303 301.25 304.83 305.75 347 BB-(38) 306-312 309 307.25 310.83 311.75 353 CC-(39) 312-318 315 313.25 316.83 317.75 359 DD-(40) 318-324 321 319.25 322.83 323.75 365 EE-(41) 324-330 327 325.25 328.83 329.75 371 FF-(42) 330-336 333 331.25 334.83 335.75 377 GG-(43) 336-342 339 337.25 340.83 341.75 383 HH-(44) 342-348 345 343.25 346.83 347.75 389 II-(45) 348-354 351 349.25 352.83 353.75 395 JJ-(46) 354-360 357 355.25 358.83 359.75 401 KK-(47) 360-366 363 361.25 364.83 365.75 407 LL-(48) 366-372 369 367.25 370.83 371.75 413 MM-(49) 372-378 375 373.25 376.83 377.75 419 NN-(50) 378-384 381 379.25 382.83 383.75 425 OO-(51) 384-390 387 385.25 388.83 389.75 431 PP-(52) 390-396 393 391.25 394.83 395.75 437 QQ-(53) 396-402 399 397.25 400.83 401.75 443 RR-(54) 402-408 405 403.25 406.83 407.75 449 ----------------------------------------------------------- UHF Band 14 470-476 473 471.25 474.83 475.75 517 15 476-482 479 477.25 480.83 481.75 523 16 482-488 485 483.25 486.83 487.75 529 17 488-494 491 489.25 492.83 493.75 535 18 494-500 497 495.25 498.83 499.75 541 19 500-506 503 501.25 504.83 505.75 547 20 506-512 509 507.25 510.83 511.75 553 21 512-518 515 513.25 516.83 517.75 559 22 518-524 521 519.25 522.83 523.75 565 23 524-530 527 525.25 528.83 529.75 571 24 530-536 533 531.25 534.83 535.75 577 25 536-542 539 537.25 540.83 541.75 583 26 542-548 545 543.25 546.83 547.75 589 27 548-554 551 549.25 552.83 553.75 595 28 554-560 557 555.25 558.83 559.75 601 29 560-566 563 561.25 564.83 565.75 607 30 566-572 569 567.25 570.83 571.75 613 31 572-578 575 573.25 576.83 577.75 619 32 578-584 581 579.25 582.83 583.75 625 33 584-590 587 585.25 588.83 589.75 631 34 590-596 593 591.25 594.83 595.75 637 35 596-602 599 597.25 600.83 601.75 643 36 602-608 605 603.25 606.83 607.75 649 37 608-614 611 609.25 612.83 613.75 655 38 614-620 617 615.25 618.83 619.75 661 39 620-626 623 621.25 624.83 625.75 667 40 626-632 629 627.25 630.83 631.75 673 41 632-638 635 633.25 636.83 637.75 679 42 638-644 641 639.25 642.83 643.75 685 43 644-650 647 645.25 648.83 649.75 691 44 650-656 653 651.25 654.83 655.75 697 45 656-662 659 657.25 660.83 661.75 703 46 662-668 665 663.25 666.83 667.75 709 47 668-674 671 669.25 672.83 673.75 715 48 674-680 677 675.25 678.83 679.75 721 49 680-686 683 681.25 684.83 685.75 727 50 686-692 689 687.25 690.83 691.75 733 51 692-698 695 693.25 696.83 697.75 739 52 698-704 701 699.25 702.83 703.75 745 53 704-710 707 705.25 708.83 709.75 751 54 710-716 713 711.25 714.83 715.75 757 55 716-722 719 717.25 720.83 721.75 763 56 722-728 725 723.25 726.83 727.75 769 57 728-734 731 729.25 732.83 733.75 775 58 734-740 737 735.25 738.83 739.75 781 59 740-746 743 741.25 744.83 745.75 787 60 746-752 749 747.25 750.83 751.75 793 61 752-758 755 753.25 756.83 757.75 799 62 758-764 761 759.25 762.83 763.75 805 63 764-770 767 765.25 768.83 769.75 811 64 770-776 773 771.25 774.83 775.75 817 65 776-782 779 777.25 780.83 781.75 823 66 782-788 785 783.25 786.83 787.75 829 67 788-794 791 789.25 792.83 793.75 835 68 794-800 797 795.25 798.83 799.75 841 69 800-806 803 801.25 804.83 805.75 847 70 806-812 809 807.25 810.83 811.75 853 71 812-818 815 813.25 816.83 817.75 859 72 818-824 821 819.25 822.83 823.75 865 73 824-830 827 825.25 828.83 829.75 871 74 830-836 833 831.25 834.83 835.75 877 75 836-842 839 837.25 840.83 841.75 883 76 842-848 845 843.25 846.83 847.75 889 77 848-854 851 849.25 852.83 853.75 895 78 854-860 857 855.25 858.83 859.75 901 79 860-866 863 861.25 864.83 865.75 907 80 866-872 869 867.25 870.83 871.75 913 81 872-878 875 873.25 876.83 877.75 919 82 878-884 881 879.25 882.83 883.75 925 83 884-890 887 885.25 888.83 889.75 931 Archive-name: wireless-cable Last-modified: Wed, February 2, 1994 ***** Wireless Cable Television - Frequently Asked Questions (FAQ) ***** Compiled by Brian J. Catlin catlin@CS.ColoState.Edu -or- bc338569@longs.LANCE.ColoState.Edu This file is Copyright (C) 1993, 1994 by Brian J. Catlin. All rights reserved. Redistribution of this file, in whole or in part, in both electronic and printed form, is permitted provided that no fee (other than direct costs) is charged and that proper credit is given. If you redistribute this file on another network, please let me know so that I can keep track of where this file goes. NOTE: Most of this information is taken from FCC Public Notices along with information sent to me by both the FCC and the Wireless Cable Association (WCA). Other information has come from numerous newspapers, magazines, and from discussions with MMDS subscribers. Items marked with three plus signs (+++) have been added or changed since the last posting. I would also like to thank Alan Larson and Craig Strachman for their numerous contributions and corrections. NOTE: For those of you wanting me to check on companies, please read the end of section 10.0. Contents: 1.0 Abbreviations used 2.0 What is wireless cable? 2.1 What is CellularVision? 3.0 What are the benefits of wireless cable to the customer? 3.1 How does wireless cable work? 3.2 What is the history of MMDS? 3.3 How does MMDS work commercially? 4.0 What frequencies are used? 4.1 How many channels can be transmitted? 4.2 What channels can be sent? 5.0 What is the range of wireless cable? 5.1 Does weather affect reception? 6.0 What equipment is in the subscriber's home? 6.1 Is wireless cable equipment reliable? 7.0 What about copyright issues? 8.0 What about security? 9.0 How are wireless cable systems regulated? 10.0 I saw one of those 'infomercials' about wireless cable. Are these companies legit? 10.1 How can I tell if a company is running a scam on me? 11.0 Is there an industry association? 11.1 Who do I contact for more information? Questions and Answers --------------------- 1.0) ABBREVIATIONS USED: ITFS - Instructional Television Fixed Service. Channels that must have a minimum of 5 hours per week of educational programming. May be leased for wireless cable usage. LMDS - Local Multipoint Distribution Service. Two sets of 50 channels in the 28 GHz band. Not yet available for wireless cable usage. MDS - Multipoint Distribution Service. Two channels that are similar to MMDS. May be used in a wireless cable system. MMDS - Multichannel Multipoint Distribution Service. Two sets of four channels each. Also, type of service known as "Wireless Cable". OFS - Private Operational-Fixed Microwave Service. Three channels that may be used for a wireless cable system. 2.0) WHAT IS WIRELESS CABLE? Wireless cable is a name given to a service that is called Multichannel Multipoint Distribution Service (or MMDS). It is a type of cable television system that offers its subscribers a mix of satellite channels by transmitting the programming over MMDS frequencies along with MDS, OFS, and ITFS frequencies, if they are available. Wireless cable uses Super High Frequency ("SHF") channels to transmit satellite cable programming over-the-air instead of through overhead or underground wires. 2.1) WHAT IS CELLULARVISION? CellularVision/Suite12 is a company that has been granted special permission by the FCC to transmit video services on a higher frequency than what wireless cable uses. They have recently started testing in the 28 GHz (or LMDS) band. It is believed that the FCC may allocate two sets of 50 channels in this band for wireless cable type service. CellularVision is hoping to provide television plus much more. With this system it would be possible to have interactive networking, grocery ordering, bank transactions, and video teleconferencing. I am not sure what all CellularVision is planning on offering during this initial testing period. However, using the 28 GHz band means sacrificing signal range. These signals aren't able to achieve even the 25-30 mile range that MMDS and other 2 GHz services are able to get, given the same transmitting power. To get around this, they are using 35 "cell sites" to transmit the programming. They hope to offer service to over 6.3 million subscribers in the region around New York City by 1995. The signal that they are sending is interleaved, which allows the transmission of large numbers of services with narrow bandwidths. 3.0) WHAT ARE THE BENEFITS OF WIRELESS CABLE TO THE CUSTOMER? Availability: Wireless Cable can be made available in areas of scattered population and other areas where it is too expensive to build a traditional cable station. Affordability: Due to the lower costs of building a Wireless Cable Station, savings can be passed on to the subscribers. 3.1) HOW DOES IT WORK? Scrambled satellite cable programming is received at a central location where it is processed and fed into special transmitters. The SHF transmitters distribute the programming throughout the coverage area, The signals are received by special antennas installed on subscribers' roofs, combined with the existing VHF and UHF channels from the subscriber's existing antenna, and distributed within the home or building through coaxial cable into a channel program selector located near the television set. Notice that you must provide a UHF and/or VHF antenna if you want the broadcast channels. This is because the Wireless Cable Box only provides a UHF/VHF tuner. Of course, not all boxes include even this feature (but most do). 3.2) WHAT IS THE HISTORY OF MMDS? It is a fairly new service that developed from MDS (multi-point distribution service) which could only send one or two channels. Originally, the FCC thought MDS would be used primarily to send business data. However, since MDS's creation in the early 70's, the service has become increasingly popular in sending entertainment programming. Because the FCC does not regulate the content of the transmission, alternative uses would not be prohibited. Today, there are systems in use all around the U.S. and in many other countries including the former Soviet Union, Australia (is yours fully functional yet?), and Canada. At the rate that the FCC has been receiving applications, it looks as if many more systems are going to be built in the U.S.. 3.3) HOW DOES MMDS WORK COMMERCIALLY? A MMDS licensee, which is similar to a broadcast station owner, leases transmission time to programmers on a first-come, first-served basis. The programmers, in turn, are responsible for designing and selling their programs to the subscriber. A MMDS applicant can choose to operate as a common carrier. In the telecommunications industry, a common carrier also may provide services such as audio only transmissions, telephone, or data. The FCC also requires that the licensee and the programmer not be related or affiliated. A common carrier offers transmission service for hire and cannot control program material or serve primarily its other business interests. (Note that this is NOT part of what is usually called "video dialtone". However, depending on the technology used, it may be possible to provide video dialtone using this method.) A MMDS applicant can alternatively choose to operate as a non-common carrier. This scenario in effect would constitute a non-common carrier wireless cable system. Also, note that a MMDS license only entitles you to FOUR channels. In order to use all 33 channels, you must apply for several different licenses from different bureaus of the FCC. This can be very costly! 4.0) WHAT FREQUENCIES ARE USED? Frequency num. of type of channel Range channels service groups ------------------------- -------- ------- ----------------- 2,150 - 2,162 MHz 2 MDS 1,2,2(A) 2,500 - 2,596 MHz 16 ITFS ABC&D 2,596 - 2,644 MHz 8 MMDS E&F 2,644 - 2,686 MHz 4 ITFS G " - " 3 OFS H 2,686 - 2,689.875 MHz 31* MMDS Response Channels * - Each channel's bandwidth is 125 KHz, and does not carry video. There are also tests being made in New York for transmitting in the 28 GHz band (LMDS). The frequencies used are 27.5 GHz - 29.5 GHz. I am not sure of how these frequencies are divided between the different services. 4.1) HOW MANY CHANNELS CAN BE TRANSMITTED? When fully implemented, wireless cable operations may have as many as 33 channels of broadcast and cable programming. This, of course, depends on which channels are already used in your area. Furthermore, 20 of the 33 channels are borrowed from ITFS services and are earmarked for educational use. This means there is a requirement to program 5 hours per week per channel of educational material. If any of these channels are being used, then any extra time can be leased by the MMDS station, if the owner of the license agrees. Approximately 90 to 150 channels may become available if digital compression is used. There are a few sites that are getting ready to test this new technology, so we'll have to wait and see how things go. Also, since the signals will be sent digitally, it is expected that the range of the signal will increase by approximately 3 times. Zenith has recently demonstrated a 16-level digital transmission system that is capable of delivering HDTV (High Definition Television). Wireless Cable operators are now allowed to place all of their educational programming onto one ITFS channel. In the past, operators have had to use the channel re-mapping function of the downconverters to make all of the educational channels appear to be on one channel. This greatly simplifies programming issues for the operators. 4.2) WHAT CHANNELS CAN BE SENT? Wireless cable systems can carry any of the typical cable channels. In the past, some channels refused to let wireless cable systems carry their signals. However, the cable re-regulation bill made channels that are available to cable companies also available to wireless cable. It can also send the 'SuperGuide' data along with similar data services. 5.0) WHAT IS THE RANGE OF WIRELESS CABLE? Wireless cable systems optimally can get a range of up to 25-30 miles. This depends largely on the terrain, transmitting power, both the transmitting and receiving equipment, and many other factors. In order to receive the signal, the transmitting and receiving antennas must be line-of-site. Because of its low startup costs, and the ability to reach places that cannot be served by traditional cable, MMDS may be feasible in certain rural areas. A range of 75 to 90 miles could be accomplished if a new digital compression system is used. (See question 3.1) 5.1) DOES WEATHER AFFECT RECEPTION? The answer to this question depends on the type of system used. For systems that transmit their programming without modification (ie. No compression or scrambling), severe fog and/or rain can cause the signal to deteriorate. From what I have heard, you can usually expect between eight to ten days per year of interrupted service. This figure, I believe, is the average for the current systems operating in the U.S.. If the programming is scrambled, the downconverter/descrambler may loose authorization sooner. On the other hand, if the programming is sent digitally, or is digitally compressed, the signal can deteriorate to a much lower level before the picture is affected. However, once the signal gets this weak, the picture will deteriorate at a much faster rate as the weather gets worse. From what I have read, the average number of days that this type of service would be interrupted, would be one day per year. (This sounds rather optimistic to me...does anyone have any info about this?) Also, the farther the receiver is from the transmitter, the sooner the picture will be affected. 6.0) WHAT EQUIPMENT IS IN THE SUBSCRIBER'S HOME? Each household subscribing to the service has a small antenna on its roof (about the size of an open newspaper) and a downconverter inside. The downconverter usually includes an addressable decoder and a VHF/UHF tuner built in. This gives it the ability to tune in broadcast channels without having to use up valuable MMDS channels. It also allows pay-per-view services and simplifies channel blocking and premium channel activation/deactivation. Also, the subscriber will need a UHF and/or VHF antenna if they want to receive broadcast channels. Recently, a new converter has been introduced that will send _all_ channels out of the converter at once. This means that you can use your TV's and your VCR's built in tuner instead of having to have seperate boxes for each. This new technology is (hopefully) going to be integrated into Wireless Cable converters as well as the traditional cable boxes sometime in 1994. 6.1) IS WIRELESS CABLE EQUIPMENT RELIABLE? Several excellent manufacturers produce antennas and downconverters for signal reception along with decoder boxes. Because the signal is broadcast over the air, it is not subject to the failures of traditional cable. However, the receiving end is somewhat more complex than most wired cable systems would use. Also, the signal is in a frequency range that may be attenuated by water (such as rain) and can be blocked by trees. There is also some risk of interference from microwave ovens operating in the area on 2,450 MHz. There are several companies that provide equipment and consulting services. If you are interested in this, you may want to pick up the latest copy of The Broadcasting Yearbook or Multichannel News. These can be found at most large libraries. 7.0) WHAT ABOUT COPYRIGHT ISSUES? Currently, wireless cable systems have assumed that they may use a compulsory license to pay for copyright issues (similar to what cable companies do today). A compulsory license enables systems to re-transmit broadcast signals for a pre-established fee to compensate producers of TV programs. The copyright office recently announced that wireless cable is NOT a cable system, therefore, these systems may not use compulsory licenses. They have decided, though, that wireless cable systems may continue to use the compulsory license for two years (until December 31, 1994). There is currently two bills that have been introduced that would extend this date. One bill would extend the date to June 1, 1995 while the other bill extends it to June 1, 1997. I will keep my eye out for this outcome. 8.0) WHAT ABOUT SECURITY? In systems that use scrambling, signal security is provided by encoding each channel and equipping the converter with a decoding device that responds to a pilot signal carrying a data stream with authorization instructions. Thus, the system is totally addressable. No (legal) converter box will have any utility unless it is authorized for service by the central computer. All channels, both Basic and Premium, are hard scrambled. Because the wireless cable system is addressable, it can also accommodate pay-per-view service. One way to defeat this is to use an illegal converter box. These are not as easy to find as the ones for regular cable systems. However, a "Universal Descrambler" will probably be able to descramble the channels. (I have not tried this). If digital compression is used, then no scrambling is needed as a compressed signal is impossible to watch. For more information on scrambling/descrambling, please refer to the "rec.video.cable-tv FYI List" posted in rec.video.cable-tv by Ed J. Gurney (egurney@vcd.hp.com). 9.0) HOW ARE WIRELESS CABLE SYSTEMS REGULATED? The FCC has specifically preempted local regulation of wireless cable frequencies, asserting that it is interstate commerce. There is no basis for local regulation of the wireless signal. Unlike cable, no public rights of way are used, and all transmission and reception equipment is on private property. Furthermore, the antennas are so similar to regular television antennas that there can be no basis for zoning restrictions. If a particular area does have zoning restrictions against antennas, they can be fought against in court (the newsgroup rec.video.satellite occasionally has these discussions). However, if you signed an agreement that restricted antennas, you may be out of luck. If you find yourself in this situation, look at the "USENET Satellite FAQ List" posted in rec.video.satellite by Gary Bourgois. Most of the information he provides about zoning restrictions applies to Wireless Cable antennas as well as TVRO (satellite) antennas. 10.0) I SAW ONE OF THOSE 'INFOMERCIALS' ABOUT WIRELESS CABLE. ARE THESE COMPANIES LEGIT? While some companies may be legit, there are some things that they don't disclose. Because of this, two companies have had temporary restraining orders placed against them. A judge has placed some of the following restrictions on them. 1. They may no longer state that applicants are "virtually guaranteed" of winning a license in the FCC lottery or that most wireless cable licenses are "highly valuable." 2. "There may be substantial delays in the awarding of any MMDS [Multichannel Multipoint Distribution System] license due to the length of time the FCC takes to process MMDS applications and award MMDS licenses." 3. That financing for wireless cable systems is hard to get, "given the relatively new nature of this field of technology and that such financing may require additional funds of the customer's own money as a condition" to obtaining system. 4. Provide a new "Risk Disclosure" statement that applicants must sign opinions and not actual values, that the winner of a MMDS lottery wins only 4 channels and that there may be competition with satellite, VCR, and other media. Temporary Restraining Orders have been placed on, or have been filed against: 1) Applied Telemedia Engineering and Management (A-TEAM) and 2) Applied Cable Technologies (ACT). If you deal with any type of application preparation firm, be very careful and read EVERYTHING. Other companies that MAY be questionable include Communications Engineering Management Services (CEMS), Decaxo Capital, Techno Source, and Western Wireless. These companies have management that were involved in a company selling cellular licenses. This company was forced out of business by the FCC for misleading customers. Other questionable companies include MMDS Technologies (also known as Metro Communications Group), Tele-Wave Technology, GMT Group (also known as National Micro Vision Systems), American Microtel Inc. (a subsidiary of Halo Holdings Group which is affiliated with First Atlantic Equity Corp. and with Codima Inc.), Continental Wireless Cable Television, Spectrum Resources Group, Midas Media Inc, UEG L.C., United Resource Group L.C., United Communications Ltd, and Application Resolution Trust (ART). I have not heard anything about any other application preparation firm. MMDS Technologies (aka. Metro Communications Group) had a restraining order placed against them, but it was later removed. Applied Telemedia Engineering and Management recently lost a court battle and they must repay their customers $100,000 for falsely representing their product. They also have to pay a $50,000 Performance Bond. You may also want to be carefull if you invest in a Wireless Cable Company in Florida which is run by Key West Wireless Partners (KWWP), Gerald Wireless, and Satellite Microcable of Florida. This company has been telling people that they are running a 32 channel system when they only have 12 channels. They have not even applied for the other 20 channels. Also, take note that in the U.S., it is ILLEGAL to enter into (or even plan on entering into) a settlement group when applying for a license. If you happen to see one of these commercials, I would appreciate it if you could write to me and give me their name and phone number so that I can get more information about different services. Please also give me information on where you saw the ad. I am currently trying to find out more about several other companies that are not listed above. For those of you who have written to me asking about different companies, please forgive me for how slow things are going. I have been totally swamped with requests and it is very difficult to find out anything about some of these companies. (They tend to enjoy calling themselves by many different names). Investigations by both federal and state agencies are continuing on many companies, and these things tend to take a lot of time. As I receive info, it will be placed here. 10.1 HOW CAN I TELL IF A COMPANY IS RUNNING A SCAM ON ME? The following article excerpt may help you. It was taken from the Los Angeles Business Journal. (Rackham, Anne "Beware of wireless cable scam, state warns public" April 20, 1992 v14 n16 pg 3(2)). (REPRINTED WITHOUT PERMISSION - Hoping to get it :-). --- BEGIN ARTICLE --- According to the Better Business Bureau and the Department of Corporations, the alleged scam works this way: * Investors are told that a wireless cable company is looking for investors who want to hold licenses for given areas that the company will service. * Each investor is asked to pay $5,000 to $7,000 and is told that the company will fill out and submit a license application in that person's name. The investor isn't told that the FCC filing fee is only $155. * The company submits several applications for one market, for which they've completed the required engineering studies, on behalf of numerous investors. These applications often don't meet the technical requirements to be successful. * Even if the investor wins a license, there may not be funding available to bring a system on line, or the business may not be profitable, much less return the outrageous sums mentioned in sales pitches. "Any time you hear someone say that they can turn $5,000 into a multi- million-dollar windfall, it's time to stop listening and hang up the phone," said Corporation Commissioner Thomas Sayles. --- END ARTICLE --- 11.0) IS THERE AN INDUSTRY ASSOCIATION? Wireless cable operators, license holders, and equipment/service suppliers have formed the Wireless Cable Association. Among its activities the WCA has established a set of industry standards, both business and technical. The WCA has also made the industry's concerns known on Capitol Hill and at Federal agencies such as the FCC, NTIA, OTA and DOJ. The WCA has also opened channels of communication with organizations such as the National League of Cities, NATOA, MPAA and the Association of State Attorneys General. 11.1) WHO DO I CONTACT FOR MORE INFORMATION? FCC Common Carrier Bureau Washington, DC 20554 (202) 634-1706 Wireless Cable Association International, Inc. 1155 Connecticut Avenue, N.W. Suite 700 Washington, DC 20036 (202) 452-7823 FAX: (202) 452-0041 Disclaimer ---------- I have no affiliation with any type of cable or broadcast system. I am definitely not an expert in these areas. I have tried, to the best of my ability, to interpret and relay the most accurate and up to date information. However, I do not guarantee the accuracy of this information as some of my sources may be biased or incorrect. For additions, clarifications, corrections, or if you just have some questions or comments, please feel free to e-mail me. -- HACK/ER --------------------------------------------------------------------------