TELECOM Digest Wed, 30 Mar 94 12:22:00 CST Volume 14 : Issue 155 Inside This Issue: Editor: Patrick A. Townson Newton PCMCIA Fax Modem to Cellular (Gregory Youngblood) Switch Problems (From OPERS-L) (Paul Robinson) Local Charges for 950 and 800 Access? (John R. Grout) History: Vail, Monopoly, AT&T (James H. Haynes) Re: Pacific Bell Voice Mail Types (Todd Inch) Re: Observations About Area Code Splits (Bob Goudreau) Re: Observations About Area Code Splits (Dave Niebuhr) Re: Observations About Area Code Splits (Danny Padwa) Re: AT&T Cellular Privacy System (Steven King) Re: Voice and Data Through PBX (David Hough) Re: Voice and Data Through PBX (James Slupsky) TELECOM Digest is an electronic journal devoted mostly but not exclusively to telecommunications topics. It is circulated anywhere there is email, in addition to various telecom forums on a variety of public service systems and networks including Compuserve and GEnie. Subscriptions are available at no charge to qualified organizations and individual readers. Write and tell us how you qualify: * telecom-request@eecs.nwu.edu * The Digest is compilation-copyrighted by Patrick Townson Associates of Skokie, Illinois USA. We provide telecom consultation services and long distance resale services including calling cards and 800 numbers. To reach us: Post Office Box 1570, Chicago, IL 60690 or by phone at 708-329-0571 and fax at 708-329-0572. Email: ptownson@townson.com. ** Article submission address only: telecom@eecs.nwu.edu ** Our archives are located at lcs.mit.edu and are available by using anonymous ftp. The archives can also be accessed using our email information service. For a copy of a helpful file explaining how to use the information service, just ask. TELECOM Digest is gatewayed to Usenet where it appears as the moderated newsgroup comp.dcom.telecom. It has no connection with the unmoderated Usenet newsgroup comp.dcom.telecom.tech whose mailing list "Telecom-Tech Digest" shares archives resources at lcs.mit.edu for the convenience of users. Please *DO NOT* cross post articles between the groups. All opinions expressed herein are deemed to be those of the author. Any organizations listed are for identification purposes only and messages should not be considered any official expression by the organization. ---------------------------------------------------------------------- Subject: Newton PCMCIA Fax Modem to Cellular From: zeta@tcscs.com (Gregory Youngblood) Date: Tue, 29 Mar 94 21:15:48 PST Organization: TCS Computer Systems eskin@brooktree.com (Michael Eskin) writes: > I am looking for recommendations for equipment and experiences in > sending data and fax from a Newton MessagePad 110 with the internal > Apple PCMCIA Fax Modem using an external interface to a Mitsubishi > 4000 pocket cellular phone. > Can it work? I am pretty much limited to 2400 baud data by the speed of > the Newton so a basic data connection is all that is needed. > I've heard reports that this should work, others that it shouldn't. I am > looking for some real data. Assuming that you can plug the PCMCIA Fax Modem into a phone line and it works, and you have the RJ11 interface for the Mitsubishi 4000, and you realize you'll have to disable dial tone detection and dial the number on the mitsubishi and press send yourself (unless you've got an interface that provides dial tone and/or can automatically dial the numbers) it should work. 2400 is no problem. I know I can send a fax at 4800 on cellular without the best conditions, and that's going thruogh ADPCM connections from the cell site to the switch (I run the cell sites and soon will have a local switch to run too). I also know 2400 is no problem data wise. Just today I did a UUCP poll via cellular at 2400/v.42 bis, as well as a few 1200 data calls as well. If your going to do 2400, then it would be a very good idea to have some form of error correction, otherwise your more prone to see lots of garbage..unless your in a great area. Faxes, I believe, have a built in form of error correction, though I don't know anything about it. Greg The Complete Solution BBS Allfiles List: Anonymous UUCP Calls Accepted 707-459-4547 (24hrs, v.32) ~/tcsbbs.lst Login: nuucp Password: nuucp Telemate Distribution Site zeta@tcscs.com Cellular Telephony Groups ------------------------------ Date: Wed, 30 Mar 1994 11:49:01 EST From: Paul Robinson Reply-To: Paul Robinson Subject: Switch Problems (From OPERS-L) The following was posted on the OPERS-L list on bitnet (Mainframe Operations). Perhaps someone on TELECOM Digest can help Mr. Osterlin with his problem. Please reply directly to him: Date: Fri, 25 Mar 1994 11:57:09 -0600 (CST) From: Bob Oesterlin Subject: Digital Telephone Switches and Modems Early last month, our local phone company (US West) replaced our "aging" analog telephone switch with a new digital one, which was designed to bring us "into the information age". Well, no sooner was the switch installed, people started having problems connecting to our dial-in service for home terminal support. The current system consists of a front-end box (made by Traqnet) and a Cisco terminal server. The problems seemed to be widespread but intermittent: - Dropped connections - Can't connect at 14.4 KB (drops back to 1200!) - Can't connect at all After some lengthy (and still ongoing) investigation, the problem turned out to be that the time bases of three digital switches involved are not in sync! The three are: - The Rochester switch (run by US West) - The IBM Rochester Local ROLM switch (local PBX) - The NPN Switch (which connects IBM to the corp network run by Advantis, Inc) Comments from our local communications rep: "I have been told that there are three national master clocks. Each phone company must sync their digital switch with one of these master clocks." "U.S. West's switch is sync'd with a master, I don't know which." "NPN's switch is sync'd with a master too, this may be the same master that U.S. West is sync'ing to but, this is not important yet." "Our ROLM switch is sync'd with NPN and cannot be changed." BTW, the problem "seems" to be getting worse as time passes. It would seem to me that this could become a widespread problem as more DSS's are used. Is someone causes a master clock to become out of step, then you could (potentially) disrupt communications over wide areas. Bob Oesterlin, IBM AS/400 Division, Dept 54T, Rochester MN 55901 oester@vnet.ibm.com (IBM IPNET: oester@rchland.ibm.com) (507)-253-4528 ------------------------------ From: j-grout@uxa.cso.uiuc.edu (John R. Grout) Subject: Local Charges for 950 and 800 Access? Date: 30 Mar 1994 17:19:23 GMT Organization: University of Illinois at Urbana Reply-To: j-grout@uiuc.edu Does the FCC permit _local_ call charges for calls to 950 exchanges or to 800 LD numbers? If so, which states/telcos do in fact allow/make such charges (at telco-operated payphones, or on lines for which telco makes a charge for each local call)? I remember having to pay for such a call at a C & P-operated payphone in Maryland ... so that might be one such state/telco combination. John R. Grout | INTERNET: j-grout@uiuc.edu [TELECOM Digest Editor's Note: Generally it is only the rip-off private payphones (COCOTS) which have charges for 950 and 800. They are not supposed to either, but they get away with it. I am surprised it was at a C&P phone. Maybe there was a programming error. PAT] ------------------------------ From: haynes@cats.ucsc.edu (James H. Haynes) Subject: History: Vail, Monopoly, AT&T Date: 30 Mar 1994 06:51:05 GMT Organization: University of California, Santa Cruz There's some interesting stuff in the new book, "The Story of Telecommunications" by George P. Oslin. Oslin is the 93-year-old former PR man for Western Union. A lot of the following is quoted from the book, slightly altered. Theodore N. Vail was related to Alfred Vail, one of Morse's partners and one of the most important inventors in early telegraphy. Theodore was a telegraph operator, got a job as a mail clerk on trains, and improved mail handling so much that he was called to Washington in 1873 to improve the railway mail. In 1876 he was appointed General Superintendent of Railway Mails. He quit to join the Bell Telephone Company in 1878. He was given charge of the territory within a 33-mile radius of New York. An experimental office was used at the Holmes Burglar Alarm Company at 194 Broadway [note that Western Union headquarters, and later AT&T headquarters was at 195 Broadway]. AT&T was incorporated in 1885 as a long-distance subsidiary of American Bell, with Vail as president. He resigned as president in 1887 because he was dissatisfied with the American Bell president and directors declaring a dividend payment instead of plowing the profits back into the company. In 1907 AT&T was was in dangerous financial condition. The bankers asked Vail to return as president. At first he refused, saying that at sixty-two he was too old, but he had just sold a South American transit development for $3 million, his wife and son had died, and he needed to keep busy, so he accepted. At the time Western Union had a near monopoly on the telegraph business. It was owned by Jay Gould and run by his man Thomas Eckert; they ran the business for their own profit and left it in seedy condition. Vail in contrast stressed service, cultivated public relations, was popular with the press for keeping the public informed. In 1909 AT&T was rich enough and WU was poor enough that AT&T bought control of WU and made Vail the president. Goes on to tell how Vail made over WU with redecorating offices and raising salaries. AT&T moved its headquarters into the WU building at 195 Broadway after a $1.3 million improvement. In 1913 the Justice Department complained about the communications monopoly and AT&T agreed to divest WU. Newcomb Carlton because president of WU and continued Vail's policies there. Vail resigned from AT&T because of ill health in 1919 and died the following year. haynes@cats.ucsc.edu haynes@cats.bitnet [TELECOM Digest Editor's Note: Thanks for that great bit of history. Most all readers of this Digest know that WUTCO and AT&T had a very long history together over the years, but little tidbits such as yours today are news to many folks. I also strongly recommend reading the book by Oslin; you'll learn much about how things came to be as they are. Without question, Ted Vail was the man who made AT&T what it is today, or at least what it was for more than half a century. PAT] ------------------------------ From: Todd Inch Subject: Re: Pacific Bell Voice Mail Types Date: Wed, 30 Mar 1994 09:48:43 PST wjhalv1@pacbell.com writes: >> Also, do Telco's provide voicemail to customers with their own PABX? > Possible but unwieldy. The PABX would have to have additional trunks > back to the CO where the Telco's VM box is. >> If so, how are the calls routed to the Voicemail equipment? I take it >> the Telco will have a centralized VoiceMail node, and will route (divert) We have third party off-site voicemail (where each mailbox has it's own real phone number but you can also select a different mailbox once you're connected to the system) and use it in conjunction with our PBX. We use Centranet (GTE's brand name for "Centrex") to allow incoming PBX calls to to be transferred to another number through the telco (flash, dial number, hang up) without tying up our PBX phone lines. We use this for forwarding to voicemail, to cell phones, and to our recently split-off sister company. Centranet also allows us to forward our main number to the main voice mailbox after hours and after the fourth ring. Since we have an 800 number which rings in on our main number, this works well for me to get my own voice mail from out of the area after hours. During business hours, I tell whoever answers in our office to please transfer me to my voicemail after reading me any paper messages first. It really helps that we have system-wide speed dial numbers programmed for each person's voicemail and the speed dial includes the required "flash". The only "kludge" is the PBX requires you to wait until it has dialed the whole number before you hang up. Fortunately the LCD display shows the number as it is being dialed so you simply hang up when you see all seven digits in the display. Interestingly, when I call and voice mail answers, I never hear any ringback tone -- I dial the number and almost immediately hear the voice mail message. I am looking into possibly getting our own in-house voicemail, however, because (1) I think it would be cheaper than the service, and (2) it would allow the message waiting lamps on the phone to light up, and (3) an auto- attendant would allow fax/modem calls via our existing 800 number and "inside" callers could bypass the receptionist person with a backdoor number. It's kinda silly -- we now get paper slips that say "check your voicemail." ------------------------------ Date: Tue, 29 Mar 1994 12:11:50 -0500 From: goudreau@dg-rtp.dg.com (Bob Goudreau) Subject: Re: Observations About Area Code Splits LincMad@netcom.com (Linc Madison) writes: > There are also some historical splits that look quite silly... > In Massachusetts, 413 has fewer than one third the number of exchanges > of either 617 or 508, and is one of the least populated NPAs. Yes, but 413 and 617 were never split from one another at all; they were both there from the start of the area code system. In fact, I remember an article in the Digest several years ago describing how 413 reportedly arrived a bit earlier than *that*, because a small region in western MA was used by AT&T to prototype area codes, and 413 was the code they tested it with. Supposedly, that's how come such a small and underpopulated region got one of the "best" area codes (by using only 8 pulls, 413 is tied for sixth place for fewest-pulses-to- dial), while Boston and the rest of MA ended up with 617. That historical anomaly also explains why the original MA area code boundary was drawn so far west, leaving 617 with two-thirds of the land area and 80+% of the people in the state. If things had been set up more rationally, 413 probably should have extended at least as far east as Worcester, and the need to split 617 (out of which 508 was born in the late 1980s) could have been deferred for many years. Bob Goudreau Data General Corporation goudreau@dg-rtp.dg.com 62 Alexander Drive +1 919 248 6231 Research Triangle Park, NC 27709, USA ------------------------------ Date: Tue, 29 Mar 94 12:46:15 EST From: dwn@dwn.ccd.bnl.gov (Dave Niebuhr) Subject: Re: Observations About Area Code Splits In TELECOM Digest Volume 14 : Issue 153 LincMad@netcom.com (Linc Madison) wrote: > I was looking at David Esan's 1/15/94 NPA-NXX list and noticed quite a > number of surprising numbers. There were a couple of instances where > I hope the answer is that a previously-effected split is not yet > reflected in the number of exchanges shown for the old area code. For > example, 212 shows 639 exchanges, and 168 for 917. I hope that the Area code 917 is not a "true areacode" in the sense that it is restricted to pagers, cell phones, and similar services, etc. NYTel could have left the exchanges in 212/718 available and/or in use after the overlay took affect. What probably happened, and maybe someone from NYTel/NYNEX who is more familiar with this could answer, is that since there were available exchanges after the overlay, more connections could be made for voice and data lines. Or, Bellcore might not have deleted them from their V&H tapes. I just can't see a company sitting around doing nothing with valuable equipment. Dave Niebuhr Internet: dwn@dwn.ccd.bnl.gov (preferred) niebuhr@bnl.gov / Bitnet: niebuhr@bnl Senior Technical Specialist, Scientific Computing Facility Brookhaven National Laboratory Upton, NY 11973 (516)-282-3093 ------------------------------ Date: Wed, 30 Mar 1994 08:45:46 EST From: padwad@psd.gs.com (Danny Padwa) Subject: Re: Observations About Area Code Splits Not sure about cellulars, but the 212-vs-917 split is still proceding in terms of pagers. While "new" numbers have been allocated out of 917 for well over a year (at least I have one much older than a year), we are still just entering the "permissive" period for the switchover for some of our older pagers. I expect (not sure) that the above mentioned cellular provider will soon be getting a surprise from NYTel (oops ... NYNEX). Danny ------------------------------ From: king@wildebeest.cig.mot.com (Steven King, Software Archaeologist) Subject: Re: AT&T Cellular Privacy System Date: 30 Mar 1994 16:49:16 GMT Organization: Motorola Cellular Infrastructure Group Reply-To: king@wildebeest.cig.mot.com I asked some questions regarding the AT&T Cellular Privacy System. Mr. Arneke kindly responded and indicated that I could post his response to the Digest. Thanks for the info, guys! From: darneke@attmail.com (David R Arneke) Date: 28 Mar 94 09:45:44 GMT Subject: Re: AT&T Cellular Privacy System Here is a more complete answer to your message of last week regarding the AT&T Cellular Privacy System. This comes from our cellular privacy product manager, Ben Bratcher (214 280-9410). 1. Is the scrambling technology simple inversion? No. The scrambling algorithm uses split-band frequency inversion, translation of the upper band's frequencies, frequency dispersion of both bands, time compression of both bands and independent time displacement of the individual bands. The combinations are determined by a key generator driven by a common key that is negotiated for each privacy activation by using a public key technique. This is the strongest scrambling algorithm available for handheld, transportable and mobile cellular subscriber equipment. 2. Is the signaling channel scrambled? How about the blank-and-burst signal sent on the voice channel to change power level or to do a handoff? Neither the signalling channel nor the inband signalling are scrambled. The Advanced Cellular Privacy System scrambles only the user's audio. However, the system is designed to maintain all functions of the cellular telephone system without degradation. 3. Is the SAT tone affected? No. The common channel interface of the cellular network is not affected by the cellular privacy system. 4. How does the mobile recognize that it's in a scrambler-capable system? How does the base site recognize that a mobile has a scrambler attached? Does the mobile scrambling unit recognize when the mobile is roaming into an incompatible system and turn itself off? The mobile system when activated sends a signal to the switch that includes its part of the public key. If the switch is scrambler- capable and the user's electronic serial number (ESN) relates to a privacy class of service mark, the switch will respond with its part of the public key and privacy is established. If there is no response from the switch, the mobile system will return a fast busy, alerting the user that privacy is not available and preventing communication until the user releases the privacy request, indicating that clear-only operation is acceptable. The Mobile Switching Equipment (MSE) will first recognize that a user has a privacy class of service from the relation of the ESN and the home or visitor location register. This causes the MSE to route the call to the MSE-based scrambler equipment. The MTSO Privacy Unit (MSE-based scrambler equipment) then recognizes the initial signal from the mobile subscriber and returns the confirmation. If a user is roaming in a non-privacy capable system and tried to initiate privacy, the mobile unit will not enter the privacy mode and will alert the user. If the mobile unit is operating in the privacy mode and enters a non-privacy capable sysyem, the mobile unit also will alert the user. Every three seconds the mobile scrambler and the switch scrambler exchange information. After five failures (allowing time for tunnels and fades), the mobile scrambler will return a fast busy call and block communication. The user can then choose to return to clear mode. 5. Is the MTSO scrambler unit part of the base site or the switch? If it's part of the base site, can a scrambled call be handed off into a cell with no scrambler unit attached? The MTSO scrambler unit is attached to the MSE and therefore is always available to cell sites associated with the MSE. Through networking, a MSE unit can continue privacy service as the mobile transits between MTSOs. 6. If there are no MTSO scrambler units available, does the subscriber get any indication that the call is being sent in teh clear rather than scrambled? Yes, as described above. 7. What is Ameritech charging for the service? Confirm this number with Ameritech, but I believe it's $14 per month. Thanks again for writing. Feel free to pass this on to Telecom Digest or anyone else who might be interested. David Arneke Media Relations Manager AT&T Secure Communications Systems david.arneke@att.com (!darneke on AT&T Mail) =================== Steven King -- Motorola Cellular Infrastructure Group ------------------------------ From: dave@llondel.demon.co.uk (David Hough) Subject: Re: Voice and Data Through PBX Date: Wed, 30 Mar 1994 09:03:52 +0000 In article Thomas Humphreys writes: > I have asked the question "Would you recommend running both voice and > data (LAN) traffic through a PBX?" of 11 individuals. 4 said yes, 7 > said no. > I am interested in what the readers of this newsgroup think about this > issue. I have to admit to some bias, because the company I work for is developing a PABX which will do just this, as well as other features. Basically, the intention is that the PABX is connected to the LAN and can accept instructions from a PC on the LAN to dial numbers, answer calls etc. This allows you to use Windoze to pop up a phone directory and click on a number to dial. The PC tells the PABX, the PABX dials the number and kicks your keyphone into life in handsfree mode. When the other end answers you can either pick up the phone handset or talk handsfree. It doesn't take much of a leap from this to be able to select a file and a destination and have the PC request the PABX to set up an external data connection to the destination and transfer the file. Even dial-on-demand routeing of individual network packets is possible. Other options include the facility for a remote user using ISDN to dial in and appear as an ethernet address on your LAN (CLI can help with security here), which is ideal for the sales force who might not have to visit the office quite so much. No we can't do all of that yet, but it is coming! It is about time the telephone was properly integrated with everything else. After all, digitized speech is only another 64kb data stream -- it has to be switched the same as all other data streams. Dave G4WRW @ GB7WRW.#41.GBR.EU AX25 dave@llondel.demon.co.uk Internet g4wrw@g4wrw.ampr.org Amprnet ------------------------------ From: jim@isnpo1.pwss.gov.ab.ca (James Slupsky) Subject: Re: Voice and Data Through PBX Organization: Alberta PWSS Telecom Date: Tue, 29 Mar 1994 21:12:57 GMT In article , Thomas Humphreys writes: > I have asked the question "Would you recommend running both voice and > data (LAN) traffic through a PBX?" of 11 individuals. 4 said yes, 7 > said no. > I am interested in what the readers of this newsgroup think about this > issue. In my opinion, there are much better products available for switching LAN traffic than a PBX. For voice, a PBX works great; for switched data, a PBX also works great (although in some cases, a packet network would be better). But for LAN data, existing LAN networking hardware/software costs less and is more mature. If you desire to connect two lans, then ISDN links through a PBX may also be an option. Regards, James Slupsky jslupsky@pwss.gov.ab.ca ------------------------------ End of TELECOM Digest V14 #155 ****************************** -------------------------------------------------------------------------------