Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: "Fred R. Goldstein" Newsgroups: comp.dcom.telecom Subject: Re: The Torsten & Jim ISDN Chat Show (was ISDN & TCP/IP) Message-ID: <2361@accuvax.nwu.edu> Date: 22 Dec 89 15:20:01 GMT Sender: news@accuvax.nwu.edu Organization: Digital Equipment Corp., Littleton MA USA Lines: 82 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 9, Issue 588, message 3 of 9 In article <2353@accuvax.nwu.edu>, euatdt@euas17c10.ericsson.se (Torsten Dahlkvist) writes... >In article <2267@accuvax.nwu.edu> munnari!cit5.cit.oz.au!jwb@uunet.uu.net >(Jim Breen) writes: >>Why is this? Is it the state of fragmentation in the US telecommunications >>industry? Does a country need monopoly suppliers like Televerket or >>Telecom Australia in order to have a working ISDN? >I can't wait to see the flames this is coing to cause! I was gonna say, "deliver me from temptation" but instead I'll take the bait. >But all is not lost yet. I forwarded the message that "there are no >TAs for sale in the US" to some appropriate people who immediately >started sprouting little $$-symbols in their eyes in the best possible >Scrooge MacDuck-style. We've made a HUGE investment in R&D on these >buggers and every sale would be a help in cutting the losses! >The problem preventing an immediate introduction is that the entire >U.S. ISDN spec is "bog-standard", i.e. U.S.A. has chosen to specify a >different method of rate adaption than the rest of the world and there >are other "sublte" differences too. There are lots of differences between US POTS and Euro-aussie POTS. For example we use 1.544 Mbps T1 and mu-255 PCM encoding instead of 2.048 Mbps E1 and A-low encoding. ISDN is a lot less different. There is no US rule for rate adaptation, since that's entirely transparent to the network. We have this system here, "competition", which basically says that the telco's fist stops at the customer's face, at the demarcation jack (reference point U). Rate adaptation occurs at a higher layer, so the telco has no say. The manufacturers here (especially AT&T and IBM) tend to favor the HDLC-based rate adaptation technique found in CCITT V.120, which was developed here. Some European-based vendors prefer the older bit-bashed technique found in V.110. And Northern Telecom has its own non-standard T-link which is fairly well established in the field. As long as the customer matches both ends, it'll work. The middle (network) needn't care. Hayes uses V.120, if I recall. >But I must ask a question to the net, U.S. readers in particular: I >know for a fact (= I was there when it happened!) that Ericsson has >been approached by one of *the* major Japanese electronics >manufacturers (no, I'm NOT going to say which one - I'm far out on a >limb as it is already!) which wanted to sell a line of ISDN phones >with built-in TA functions. Essentially a small feature-phone with a >V.24, X.21 or (I think, but memory is vague) X.25 connector. We tried >it and found that with minor changes in CO software it could be used >with our CO (remember I said our implementation is *very* close to the >international standard. We like to think it's *the* closest one on the >market at present!). "ISDN Phones" are a classic example of technology missing the market. ISDN makes a terrible desktop data solution. Most terminal-host connectivity is within the building (local area). ISDN, no matter how you slice it, costs more for this than a LAN with terminal servers. And the terminal servers tend to offer more flexibility, features, etc. Better, faster, cheaper. Pick three. So why waste ISDN by putting it on the desktop? Yes, I remember the early "integrated voice/data PBX" days, and helped put a rack of PBX data modules next to a VAX. Ugly, costly, and happily abandoned to the dregs of history. ISDN's strength in the data world is when you go beyond the LAN. ISDN to the home, or ISDN between locations. It makes a great modem replacement. But who in their right mind uses modems to dial down the hall? ISDN voice/data phones are about as useful as phones with built-in V.22bis modems: No reason not to put a phone on a modem, but not a mass market item. Fred R. Goldstein goldstein@carafe.enet.dec.com or goldstein@delni.enet.dec.com voice: +1 508 486 7388 Do you think anyone shares my opinion, let a long a big corporation?