Kim.Fosbe@uunet.uu.net> (05/19/91)
I already know about what ISDN is and about all those wonderful things that it will do which we will wonder how we got along without. What I don't know is just how it will effect those of us who use regular plug-in modems. Nobody seems to know this. Will ISDN make our modems obsolete? Is it true that all we will have to do is plug in an RS232 cable from the PC port to the phone and dial up any system like we do now? Is there a way to use your plug-in modems when you have ISDN at home? Has anybody ever thought of that? Also, is there a way to use your answering machine when you get ISDN? Another question while I am on the subject. Are these black AT&T digital phones that are replacing the hold-button phones in offices actually ISDN phones? One guy tells me they are and another guy tells me no. Both of them are electronic people. Full of questions, aren't I? Thanks in advance for any and all information. Ybbat (DRBBS) 8.9 v. 3.13 r.5 [200:5010/666@metronet] DRBBS -- Keep The Royals in Omaha (200:5010/666.0)
Jeff.Scheer@uunet.uu.net> (05/20/91)
Kim, I think that the black AT&T phones in offices are the Merlin or Merlin Plus systems. That would put them (I believe) in the Digital train or ISDN. As for the modeming question run that one by the other persons here as I am a lowly end-user and am trying to keep up with all that is going on in the telecom world, although some of the acronyms are enough to drive me up a punch down block. The .COMmand Center (Opus 1:5010/23) [Mooderator's Note: I believe a message earlier today indicated that the Merlin phones are not necessarily ISDN equipped. The phone has to actually say so. When you come down off the punch down block, you can look up all the telecom acronyms you ever wanted to know and then some by pulling the three glossary files from the Telecom Archives. Submitted by different sources, they have hundreds of terms to help you in understanding what you read here. (ftp lcs.mit.edu) PAT]
oberman@ptavv.llnl.gov (05/20/91)
In article <telecom11.376.4@eecs.nwu.edu>, ivgate!Kim.Fosbe@uunet.uu. net (Kim Fosbe) writes: > I already know about what ISDN is and about all those wonderful things > that it will do which we will wonder how we got along without. > What I don't know is just how it will effect those of us who use regular > plug-in modems. Nobody seems to know this. > Will ISDN make our modems obsolete? Is it true that all we will have > to do is plug in an RS232 cable from the PC port to the phone and dial > up any system like we do now? Is there a way to use your plug-in > modems when you have ISDN at home? Has anybody ever thought of that? > Also, is there a way to use your answering machine when you get ISDN? > Another question while I am on the subject. Are these black AT&T > digital phones that are replacing the hold-button phones in offices > actually ISDN phones? One guy tells me they are and another guy tells > me no. Both of them are electronic people. Full of questions, aren't I? Plug in modems are analog devices and simply won't work with ISDN. ISDN does provide RS-232 connectivity at the TE (ISDN for Termial Eqipment) in the form of separate boxes, modules for telephones (my office phone has a DB25 in the back), BRI boards for computers and, no doubt many others yet to be invented. See my previous post for possible ways to get from ISDN to analog modems. Once everyone has ISDN modems will be obsolete. But for the next couple of centuries they will still be around. I suspect that either LECs or private companies will provide ISDN to modem service to get from analog to ISDN and back. Our site has its own modem pool on the analog side of our switch, but most folk can't afford their own ISDN switch. (We have a 5ESS.) Bottom line -- ISDN is a pure digital medium. Analog equipment will NOT work with it. Period. Answering systems included. I expect two products to appear to take care of this. ISDN answering machines and a limited ISDN to analog converter. The latter would work well with things like answering machines. I don't know about modems. In theory they would work, but I suspect that there might be interoperability problems. If the black AT&T phone says ISDN on the corner, it's ISDN. Otherwise it is not. Merlins look almost identical to ISDN phones. They are digital and share components with ISDN sets, so the confusion is reasonable. But they are very different from "real" ISDN phones. My desk set looks "just like" mu old Merlin phone except for a few more buttons and a two line LCD alpha-numeric display. R. Kevin Oberman Lawrence Livermore National Laboratory Internet: oberman@icdc.llnl.gov (415) 422-6955 Disclaimer: Don't take this too seriously. I just like to improve my typing and probably don't really know anything useful about anything. Especially anything gnu.
"Fred R. Goldstein" <goldstein@delni.enet.dec.com> (05/21/91)
In article <telecom11.376.4@eecs.nwu.edu>, ivgate!Kim.Fosbe@uunet.uu. net (Kim Fosbe) writes... > Will ISDN make our modems obsolete? Is it true that all we will have > to do is plug in an RS232 cable from the PC port to the phone and dial > up any system like we do now? Is there a way to use your plug-in > modems when you have ISDN at home? Has anybody ever thought of that? > Also, is there a way to use your answering machine when you get ISDN? If both ends of the call are on ISDN, then modems are obsolete: ISDN gives you 64 kbps dial up. You'll still need an ISDN Terminal Adapter (TA) to convert RS232 to ISDN, though; it's like a modem but a tad bit faster. Of course if you have ISDN at only one end, it had better have a modem if it wants to communicate with an analog line! That's possible too ... Some ISDN networks may also provide a modem pool service. The answering machine question, though, brings up another nit about ISDN: For the average residence, ISDN makes no sense for _voice_. You'd need a new ISDN answering machine, and I've not seen one yet, and it wouldn't be cheap. Better to have a TA to adapt analog lines and devices (phones, answering machines) to ISDN, using a different TA to handle the high-speed data. Note that only one phone can be on a call at a time using ISDN digital phones, so an analog phone will work better! (It needs a TA, which generically means any devices that adapts non-ISDN devices to run over ISDN, phone or data.) > Another question while I am on the subject. Are these black AT&T > digital phones that are replacing the hold-button phones in offices > actually ISDN phones? One guy tells me they are and another guy tells > me no. Both of them are electronic people. Full of questions, aren't I? AT&T 7500-series sets are ISDN. The 7400-series sets aren't. ISDN sets are generally found behind Centrex, while the non-ISDN sets (cheaper) are typically found behind PBXs. They look similar. Fred R. Goldstein Digital Equipment Corp., Littleton MA goldstein@delni.enet.dec.com voice: +1 508 952 3274 Do you think anyone else on the planet would share my opinions, let alone a multi-billion dollar corporation?
dts@husc6.harvard.edu> (05/22/91)
Boxes to make analog devices work over ISDN are supposed to be available. It will be impossible to roll out ISDN for residential service without such gizmos, and they'd better have enough battery backup potential for keeping the line running in the event of an AC failure. Your comments regarding ISDN and analog not interacting ever is perhaps the way things will be at bigger corporations, but not elsewhere. The 64000 BPS pipe provided by an ISDN B channel is the same as what your current analog voice circuit gets digitized into in the C.O. today. The only difference in service between an Analog to ISDN converter in your house and running analog to the CO is where the Analog/Digital conversion takes place. There is a big advantage in doing the A/D conversion closer to your house rather than at the C.O. since the analog lines pick up noise without a means for compensation. SLC-96 units provide a similar A/D conversion outside the C.O. Daniel Senie UUCP: uunet!lectroid!peanut!dts Daniel Senie Consulting ARPA: peanut!dts@lectroid.sw.stratus.com 48 Elm Street CSRV: 74176,1347 Clinton, MA 01510 TEL.: 508 - 365 - 5352 [Moderator's Note: A new mailing list discussing ISDN is getting under way. For information on how to subscribe, read the final message in this issue of the Digest. PAT]
"Jonathan M. Zweig" <zweig@parc.xerox.com> (05/23/91)
oberman@ptavv.llnl.gov writes: [stuff deleted] > Bottom line -- ISDN is a pure digital medium. Analog equipment will > NOT work with it. Period. Answering systems included. I expect two > products to appear to take care of this. ISDN answering machines and a > limited ISDN to analog converter. The latter would work well with > things like answering machines. I don't know about modems. In theory > they would work, but I suspect that there might be interoperability > problems. GACK! This is in direct disagreement with the existence of POTS interface doohickies I have seen demos of. Basically a box that has an RJ11 jack for a vanilla phone, and just enough ISDN smarts in it to accept dial strings, produce ring voltages, etc. I admit it's pretty horrid to think of turning my data into analog screamishness so it can get redigitized a meter away, but it would certainly work to plug a Trailblazer into the analog jack of a suitably equipped ISDN phone. 64,000 digitizations per second is 64,000 digitizations, whether my CO's 5ESS switch does it, or the box on my wall. Johnny Phone
oberman@ptavv.llnl.gov (05/28/91)
In article <telecom11.393.7@eecs.nwu.edu>, zweig@parc.xerox.com (Jonathan M. Zweig) writes: > oberman@ptavv.llnl.gov writes: > GACK! This is in direct disagreement with the existence of POTS > interface doohickies I have seen demos of. Basically a box that has > an RJ11 jack for a vanilla phone, and just enough ISDN smarts in it to > accept dial strings, produce ring voltages, etc. > I admit it's pretty horrid to think of turning my data into analog > screamishness so it can get redigitized a meter away, but it would > certainly work to plug a Trailblazer into the analog jack of a > suitably equipped ISDN phone. 64,000 digitizations per second is > 64,000 digitizations, whether my CO's 5ESS switch does it, or the box > on my wall. I have become aware of such things, and I'm sure they work for many applications, but when AT&T bid on our phone system, they promised such a capability. They failed to deliver and, I assume, paid a penalty for failing to meet contractual obligations. 64 KHz is 64 KHz, (but not really 64,000 digitizations per second). But that does NOT mean that plugging in a TrailBlazer will just work. In fact, Trailblazers don't work on some multiplexed analog lines. I am nowhere nearly expert enough on the details of V.32 or PEP to say what difficulty might be encountered, but AT&T told us that "it is not possible". And paid for the opportunity to say it. That does NOT make it right. In fact, it's probably wrong. But it does imply that it is not trivial. And they made it clear that an analog connection to handle answering machines was a lot easier, though not as trivial as it sounds. Things like ring voltage and lack of feedback to the ISDN side of the circuit make it trickier than it seems at first. R. Kevin Oberman Lawrence Livermore National Laboratory Internet: oberman@icdc.llnl.gov (415) 422-6955 Disclaimer: Don't take this too seriously. I just like to improve my typing and probably don't really know anything useful about anything. Especially anything gnu.