Path: utzoo!telecom-request Date: 28 May 91 16:36:07 GMT From: oberman@ptavv.llnl.gov Newsgroups: comp.dcom.telecom Subject: Re: A Very Simple ISDN Question Message-ID: Organization: TELECOM Digest Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 405, Message 4 of 7 Lines: 45 In article , 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.