TELECOM Digest Thu, 15 Oct 92 00:43:20 CDT Volume 12 : Issue 781 Index To This Issue: Moderator: Patrick A. Townson Re: East German Pay Phone (Martin McCormick) Re: East German Pay Phone (Dick Rawson) Re: East German Pay Phone (Tom Coradeschi) Re: East German Pay Phone (Eric Tholome) Re: College Phone System AGAIN! (Scott Fybush) Re: College Phone System AGAIN! (Jeff Dubin) Re: N-1-1 Codes for Relay Services (Curtis E. Reid) Re: N-1-1 Codes for Relay Services (Ralph Hyre) Re: Why No Sprint Service Here Since Thursday? (Tom Streeter) Re: Why No Sprint Service Here Since Thursday? (David G. Lewis) Re: Seeking Information on SS7 Packets (Alan L. Varney) Re: Seeking Information on SS7 Packets (Jack Adams) ---------------------------------------------------------------------- Subject: Re: East German Pay Phone Date: Wed, 14 Oct 92 11:54:54 -0500 From: martin@datacomm.ucc.okstate.edu A few ways one could have a hook switch with no moving parts are: The ear piece of the handset could have a reed switch in it and the hanger could be magnetic. When the receiver was on the hook, the reed switch could be pulled open. Another variation on that idea would be to have a Hall-effect transistor as the switching device and the magnet in the hanger, as before. I have actually seen such a chip. It is a three-terminal device. You put power on one pin, ground another, and the third one is open until a magnet is brought near, at which time it suddenly goes to ground. It's really neat. Finally, it's possible that there could be a photo cell in the hanger with a light source so that the handset blocks it when in place. My own belief is that it is a magnetic switch. It's quite possible that the switching element is in the metal plate near the hanger and that the permanent magnet in the ear piece of the handset is what actuates it. If a reed switch is used, the metal plate near the hanger would be a better location for it because those things tend to open and close when beat on. The normal movements of a handset in a user's hands would probably cause this to happen all the time which would be quite frustrating to say the least. Martin McCormick WB5AGZ Stillwater, OK O.S.U. Computer Center Data Communications Group ------------------------------ From: drawson@sagehen.Tymnet.COM (Dick Rawson) Subject: Re: East German Pay Phone Date: 14 Oct 92 18:58:58 GMT Organization: BT North America (Tymnet) >> The most interesting thing is that the hanger for the handset did >> not appear to move for off-hook indication. > That reminds me. At the end of May I was in what used to be East > Berlin, and made a call from a pay phone there ... > That phone, too, had no obvious moving parts for off-hook detection. > ... Anyone know how it worked? Speculation: perhaps the phone box detects the permanent magnet that is likely to be in the handset's earpiece. A reed relay would be low-tech and reliable (like the burglar-alarm door switches), but I question if it is sensitive enough. A Hall-effect flux detector would work, but is it economical enough? A metal panel shouldn't bother a STEADY magnetic field, although it attenuates an alternating field. Dick ------------------------------ Date: Wed, 14 Oct 92 9:22:37 EDT From: Tom Coradeschi Subject: Re: East German Pay Phone Organization: Electric Armts Div, US Army ARDEC, Picatinny Arsenal, NJ msb@sq.com (Mark Brader) writes: > The most interesting thing is that the hanger for the handset did > not appear to move for off-hook indication. > That reminds me. At the end of May I was in what used to be East > Berlin, and made a call from a pay phone there (specifically, it was > in one of the city center S-Bahn stations, either Friedrichstrasse or > Alexanderplatz). > That phone, too, had no obvious moving parts for off-hook detection. > The hanger was metal, and the other end of the handset rested against > a small metal plate, so I wondered if it was be passing a small > current through the handset, but the handset seemed to be plastic. > Anyone know how it worked? Magnetically operated reedswitch would be my guess. (Magnet in handset, reedswitch in phone housing, driving a relay if needed [shouldn't be].) > There were no directories, so I needed to call directory assistance to [...] > After several repetitions of this, I pulled out the guidebook I was > carrying and found the *3*-digit code that *it* had given for dialing > West from East Berlin (849, I think). I tried this and it worked. > The mind boggles. Now that I think of it, it also rather boggled at > the fact that, unless my hotel listing included some out-of-date > numbers, West Berlin telephone numbers could be five, six, seven, or > eight digits long ... Typical, actually. I've had occasion to deal with US Army installations in Germany (former West Germany, naturally:-}). One guy, in particular, has a ten-digit phone number and an eleven-digit fax number (different exchanges, although within the same city). tom coradeschi <+> tcora@pica.army.mil ------------------------------ From: tholome@bangalore.esf.de (Eric Tholome) Subject: Re: East German Pay Phone Date: 14 Oct 92 13:50:24 GMT Reply-To: tholome@bangalore.esf.de (Eric Tholome) Organization: ESF Headquarters, Berlin, FRG In article , msb@sq.com (Mark Brader) writes: > [stuff deleted] I knew East and West Berlin > were still separate for telephone purposes, but I was still surprised > when they were surprised that I didn't say "West Berlin" when I gave > the address. Well, I thought I'd let you know that the two (east and west) Berlin telephone networks are now pretty much integrated. We (in West Berlin) recently received a letter telling us that from now on, we wouldn't have to dial any special code to reach East Berlin. In other words, at least from the west, one can dial ANY Berlin number after the dial tone, without having to figure out in which part of the city it is. I assume that either your experience is a couple months old, or it isn't symmetric, i.e. people calling from East Berlin still have to differentiate the two types of calls. I must admit I've never given a call from East Berlin ... [stuff deleted] West Berlin telephone numbers could be five, six, seven, or eight digits long ...] I believe this is true in all Germany. They like to be able to give short telephone numbers to big advertisers or companies. I must say I don't really like it: you never know whether you got all the digits! Also, people never know how to group the digits. For example, my number at work has eight digits, which I can write 82 09 03 25, but my home number only has seven digits, which I usually write 262 51 22. Some people write them differently (e.g. 820 903 25). That's kind of confusing. Eric Tholome ESF Headquarters internet: tholome@esf.de Hohenzollerndamm 152 UUCP: tholome@esf.uucp D-1000 Berlin 33 Ph.: +49 30 82 09 03 25 Germany Fax: +49 30 82 09 03 19 ------------------------------ Date: Tue, 13 Oct 92 21:10 EDT From: fybush@unixland.natick.ma.us (Scott Fybush) Subject: Re: College Phone System AGAIN! kupiec@hp800.lasalle.edu (Bob Kupiec) writes: > ...at LaSalle University. We have been running on > two PBX's (one for campus offices, one for campus dorms) and AT&T ACUS > for the dorms for the past few years. We were equipped with free > local calls, free 800, Call Waiting, Three-Way Calling and Call > Forwarding with all the frills. This reminds me of my experience at Brandeis University, from which I graduated this past May. Single PBX there, free local calls, call-waiting for $25 a semester (a bit steep compared to $2.58 a month from NETel), free 800, no other frills. > Now things have changed ... > Everything was fine until I returned for the fall semester. They > decided to consolidate the two switches into one NCR switch. So far > there has been nothing but trouble. > 800 access to all 800 numbers are BLOCKED (except for the 445 ACUS > prefix) and without an ACUS plan you can't call 800! What about > calling card users? The Telecom Operations guy gave me the useless > "800 numbers were forwarded to 900 numbers and we don't want to be > stuck with the bill" response. When the first of the 800-to-900 scams appeared in 1991, I paid a visit to the system administrator (someone who it's good to know ... if you can get this person to tell you the truth, they can be extremely valuable) to let her know the scam existed. Her response wawas to block that single number. Better than your campus' solution, to be sure, but still mostly a reactive solution. The campus system manager almost has to get burned by a number before knowing that it should be blocked. And of course the current user of Mystic Marketing's old 800 number is now inaccessible from Brandeis. > Call Waiting sometimes does not work for incoming off-campus calls. > There is NO way to block Call Waiting! This give me a fit, because > how am I supposed to use the modem?! At least Brandeis gives students the option of not buying the service. Now that I have REAL phone service from NETel, I do have Call Waiting (not my choice :-), but I can turn it off with *70. > Also, the Telecom Operations person told me one of the tie lines seems > to be messed up because some on-campus calls connect with very faint > audio. He also can't seem to find which one it is to disable it > either. > No Three-Way and no Call-Forwarding enabled. Also, and the previous > poster mentioned, there is NO WAY to get a local or LD Operator! NO > 9-0 and no 9-00. Only the campus operator. > I just hope that 9-911 works in case of an REAL emergency! (How > should I test this?) 9-911 is probably blocked, but for good reason. If there's an emergency on campus, you should be calling your campus public safety dispatcher. They can contact ambulance, fire, or local police if needed. However, a well-designed system should intercept 911 or 9-911 and send them to the campus dispatcher. How many people remember that the campus emergency number is, in my case, 3333? > The latest development is the ACUS codes don't even work! For the > last few days there has been no way to call home from the campus > telephones. I think I should ask for my "phone service" deposit back > because I sure don't get any. You have my condolences. My feeling in reading the last few posts on this thread, as well as in my dealings with Brandeis Telecom (check the archives for plenty of griping about them!) is that campus telecommunications needs should be handled by professionals. If the campus can't afford to hire someone who can manage the system properly -- and that means making sure there are enough trunks in and out to handle all traffic, ensuring access to all available telecom services that an "off-campus" user would have access to (and this includes 800, 900, 700, 10XXX-0, 950, weather and time/temp lines, and international direct dialing), fixing problems with the system quickly and properly, and at the same time providing protection against fraud -- then the campus should leave the job to the pros at the local telco. I'd rather pay $15 or $20 a month for decent, reliable, telco POTS service than have to put up with the really cruddy "service" that so many of these campus systems seem to offer. I'm paying a total of about $30 a month for service now (not including toll charges and taxes), and it is far superior in all regards to the Brandeis system. ------------------------------ Organization: The American University - University Computing Center Date: Wed, 14 Oct 1992 13:32:25 EDT From: Jeff Dubin Subject: Re: College Phone System AGAIN! You have a problem with faint audio also? Twice a week or so, I'm talking normally and all of a sudden I can't hear the other person, even though s/he can hear me fine. I guess my phone service isn't so bad after comaring it to yours! If you don't already, I'd demand a pay phone on your floor. At least that way you can call somewhere! Jeff Dubin jdubin@world.std.com jd2859a@american.edu ------------------------------ Date: 14 Oct 1992 09:34:33 -0400 (EDT) From: Curtis E. Reid Subject: Re: N-1-1 Codes for Relay Services In a message received on 12 Oct 1992, 18:28 attmail.com!cinpmx! cdid!rhyre%cubs@attmail.com wrote: >> Dialing 5-1-1 or 7-1-1 from anywhere in the country to access a >> state's relay service will be easy to remember, quicker, and will > Wouldn't this be a case where a 950-XXXX number is warranted? > (950-TRS1 or 950-TDD1). One could even imagine the XXXX mapping > the the LD carriers which seem to provide these relay services > in many states. > This would seem to be easier to implement for most LECs, and > it would also consume less of the remaining number space. An > added benefit is that 950 numbers typically incur no message > unit charges or other toll charges. You're probably right; however, I believe that 950-xxxx is a local implementation and so is the N-1-1. It still requires the FCC to make them consistent throughout the country. Also, it's easier to remember the N-1-1 than the 950-xxxx number which is probably why TDI made the proposal to FCC. As a matter of fact, there is one state that did a similar implementation: Maine. The Relay Service numbers for Maine Residents are: 955-DEAF and 955-DPRS. Curtis E. Reid CER2520@ritvax.isc.rit.edu Rochester Institute of Technology/NTID REID@DECUS.org (DECUS) P.O. Box 9887 716.475.6089 TDD/TT 475.6895 Voice Rochester, NY 14623-0887 716.475.6500 Fax ------------------------------ From: cinpmx!cdid!rhyre%cubs@attmail.com Date: 14 Oct 92 12:47:52 GMT Subject: Re: N-1-1 Codes for Relay Services > Dialing 5-1-1 or 7-1-1 from anywhere in the country to access a > state's relay service will be easy to remember, quicker, and will Wouldn't this be a case where a 950-XXXX number is warranted? (950-TRS1 or 950-TDD1). One could even imagine the XXXX mapping the the LD carriers which seem to provide these relay services in many states. This would seem to be easier to implement for most LECs, and it would also consume less of the remaining number space. An added benefit is that 950 numbers typically incur no message unit charges or other toll charges. ------------------------------ From: streeter@cs.unca.edu (Tom Streeter) Subject: Re: Why No Sprint Service Here Since Thursday? Organization: University of North Carolina at Asheville Date: Wed, 14 Oct 1992 20:57:39 GMT In article shri@nyx.cs.du.edu (H. Shrikumar) writes: > It's due to the recent torrential rains in western SC, that flooded a > Sprint DMS-250 switch (that was underground I believe). Will take > quite a while to get things back to normal. We are affected here in > central and eastern NC as well. My primary private net and 800 service > is with Sprint. Hmmmmmmm ... odd. I'm with Sprint in Asheville (western NC) and haven't had any problems. We're just 50 miles or so from Greenville. I *am* glad it quit raining, though. Tom Streeter | streeter@cs.unca.edu Dept. of Mass Communication | 704-251-6227 University of North Carolina at Asheville | Opinions expressed here are Ashevillen, NC 28804 | mine alone. ------------------------------ From: deej@cbnewsf.cb.att.com (david.g.lewis) Subject: Re: Why No Sprint Service Here Since Thursday? Organization: AT&T Date: Wed, 14 Oct 1992 13:58:24 GMT In article waugh@rtpnet05.rtp.dg.com (Matthew Waugh) writes: > I haven't seen anything on this, and I'd expected people to be jumping > all over it. > Sometime on Thursday evening 10/8/92 the SPRINT switching centre in > Fairfax, South Carolina, went down completly. Various "rumors" abound, > most of which involve the switch being under 18 feet of water. We're > located in North Carolina, and all our SPRINT switched service is > routed via that switch. Certainly on Friday people in the area with > SPRINT 800 service were not getting any calls sent their way. > It's 16:00 EDT on 10/13/92, still no service. We have dial-tone on the > trunk, and get an all circuits are busy if we try and make a call. Funny, I haven't seen that Sprint commercial lately. You know, the one where Candice Bergen says "Sprint didn't go down and leave a kazillion people stranded ..." ;-) David G Lewis AT&T Bell Laboratories david.g.lewis@att.com or !att!goofy!deej Switching & ISDN Implementation ------------------------------ Date: Wed, 14 Oct 92 10:00:29 CDT From: varney@ihlpk.att.com (Alan L Varney) Subject: Re: Seeking Information on SS7 Packets Organization: AT&T Network Systems, Lisle, IL In article raum@isoa3.ba.ttu.edu (Raum Pattikonda) writes: > I am not very familier with SS7 protocols. I would like to know if the > SS7 packets contain the calling card number information for the calls > made using the calling card. Can someone also please sugest a good > book on SS7. Standard SS7 "packets" (this is telephony, so they are called "messages") do not currently contain CC#. However, T1S1.3 is well along in the process of standardizing the encoding and transport of this information, and delivery via ISDN. I'm not aware of any standards for determining the need for or method of collection, etc. that would result in such transport/delivery; that's probably viewed as an Operator Systems issue, so far. I won't recommend any books specifically, but most of the very recent ones on "ISDN" have a good section on SS7. The local Barnes & Noble usually has a few in the Computer Communications section, and can order others. Note that these are tutorial-level and are not a replacement for the real ISDN standards, available in the Q.7xx CCITT "Blue" book or as series of T1 standards from ANSI. Bellcore clients (the "RBOCs" generally) also use a collection of requirements that are more "services" oriented; briefly, the main ones for voice calls are TR-NPL-000246 (basic SS7), TR-TSY-000317 (intra-LATA voice via SS7) and TR-TSY-000394 (inter-LATA voice via SS7). Al Varney - MY opinion, of course. ------------------------------ From: vixen!jadams@uunet.UU.NET (22475-adams) Subject: Re: Seeking Information on SS7 Packets Organization: Bellcore, Livingston, NJ Date: Wed, 14 Oct 92 14:00:21 GMT In article , raum@isoa3.ba.ttu.edu (Raum Pattikonda) writes: > I am not very familier with SS7 protocols. I would like to know if the > SS7 packets contain the calling card number information for the calls > made using the calling card. Can someone also please sugest a good > book on SS7. For Alternate Billing Service (ABS) or Line Information Data Base (LIDB) queries, yes, the calling card number is included in the Transaction Capabilities Part (TCAP) of the SS7 message. Different applications CLASS(R), 800, LIDB, and AIN construct their message components differently according to published BELLCORE Technical Requirements documents. In terms of recommending *A* good book, I am clueless. Perhaps, if enough interest exists, I (all co-authors are welcome to contribute) might want to undertake the effort. If there exists one or more good texts on the subject, I'd rather not. Jack (John) Adams Bellcore NVC 2Z-220 (908) 758-5372 {Voice} (908) 758-4389 {Facsimile} jadams@vixen.bellcore.com kahuna@attmail.com ------------------------------ End of TELECOM Digest V12 #781 ******************************