Telecom-REQUEST@MIT-XX.ARPA (10/28/85)
From: Moderator <Telecom-REQUEST@MIT-XX.ARPA> TELECOM Digest Sunday, October 27, 1985 8:30PM Volume 5, Issue 57 Today's Topics: Rochester telephone service Re: TELECOM Digest V5 #56 Why the Vadic 3400 protocol is still alive ! Re: High-speed modem query Re: Modems with Builtin \"Protocol\"s Data Access Lines dialing 617 460 .... Re: TELECOM Digest V5 #54 ---------------------------------------------------------------------- Date: 25 Oct 85 19:53 EDT (Fri) From: _Bob <Carter@RUTGERS> Subject: Rochester telephone service From: Jon Solomon <JSOL at MIT-XX.ARPA> Dialing your dial slowly has nothing to do with how fast the incoming trunks at Hamilton, NY. receives their tones. I would say that if you are experiencing that symptom, that your local switch is where the difficulty lies... I guess I was assuming the tones for 315 connected me to a line (virtual or actual) which carried the rest of the tones to the Hamilton CO where the 824-XXXX did what ever necessary to connect to the called instrument. I suppose that is a pretty dumb assumption. Just how does it work (if you can explain in terms for the very simpleminded)? Does my CO actually do route-planning to the one particular phone being called? _B ------------------------------ Date: Fri, 25 Oct 85 19:59 EDT From: Frankston@MIT-MULTICS.ARPA Subject: Re: TELECOM Digest V5 #56 I'm still trying to get off the digest edition of this mailing list. Any advice would be appreciated. Thanks. ------------------------------ Date: Sat, 26 Oct 1985 01:05 EDT From: "David D. Story" <FTD%MIT-OZ @ MIT-MC.ARPA> Subject: Why the Vadic 3400 protocol is still alive ! 212a being better is a lot of sh&t. Bell originally wouldn't sell their modems and in the lease package they billed the user on data phone rates. Bell also wouldn't give out their filter specs, sell them, or anything else which in turn created the pocket for Vadic. If you have noisy lines (and remember that this is recent history before all the line conditioning and that's where Bell put the data phones) the 3400 protocol is much better (cleaner). The 103 is coupled. And I don't think Vadic or Hayes Anderson (only around for 2? years for their licens) ever had an acoustic coupler running 3400. The HA uses their coupler for 103 only I believe. What remains to be seen is if Vadic comes out with harmonic 2400 modems that are cleaner that what is possibly already there. Maybe 4800 - 9600 ! Bell works on a feedback filter while Vadic works onharmonics. The Bell filter had to let some noise in their frequency range pass while the Vadic doesn't won't and never will. Preferable tkeep the creepy micro people of thmainfthere shouldn't exist a 103 or a 212a answer option strap so then stupid managers couldn't set up that way ! Cut those straps ! ------------------------------ Date: 24 Oct 85 12:16:30 GMT From: Bob Halloran <vax135!petsd!pedsgd!bobh@Ucb-Vax.ARPA> Subject: Re: High-speed modem query In article <120@sandia.UUCP> pjatter@sandia.UUCP writes: >We are currently evaluating high-speed (i.e., > 1200 baud) modems >to link our remote terminal users to our Vax. > >There seem to be plenty of options in the 2400 baud arena, but now >we're getting greedy and are looking at some of the 9600 baud >modems which are beginning to become available. Does anyone have >any experience with 9600 baud modems (preferrably asynchronous)? >The only companies I've seen advertise so far are: > > Electronic Vaults (Reston, VA): upta 96 (asynchronous) > Universal Data Systems (Huntsville, AL): UDS 9600 A/B (synchronous) Another option which just arrived is the Telebit modem, being marketed by Digital Communications Associates (PC Irma coax interface board et al). This is a proprietary asynch scheme for 9600 b/s which purportedly can adapt to changing line conditions on the fly in increments of <100 b/s. They do this by subdividing the bandwidth into numerous subchannels to spread out the information. I seem to recall price for the stand-alone unit to be about $2400. I mention this since, as they are currently selling for the volume PC marketplace, they are likely to become a de facto standard. I believe the information number is 1(800) TELEBIT. Bob Halloran Sr MTS, Perkin-Elmer DSG ============================================================================= UUCP: {decvax, ucbvax, most Action Central}!vax135\ {topaz, pesnta, princeton}!petsd!pedsgd!bobh USPS: 106 Apple St M/S 305, Tinton Falls NJ 07724 DDD: (201) 758-7000 ------------------------------ Date: Sat, 26 Oct 85 00:04:27 PDT From: ihnp4!ho95e!wcs@UCB-VAX.Berkeley.EDU Subject: Re: Modems with Builtin \"Protocol\"s In article <2306@brl-tgr.ARPA> fischer@RAND-UNIX.ARPA writes: >I looked (briefly) into the new 2400 baud modems for use with my Xenix >system. The dealers all push versions with a built-in protocol called >MNP. This protocol handles retries of bad characters, BUT (e.g., beware) >it is not really suitable for use on communications where the underlying >software already has a protocol. > >With uucp, the MNP flow control will be incompatible, and thus one will >have to disable MNP. > >With Kermit, MNP is likely to play havoc .... flow control .... >... Emacs with ... control-s or control-q, I'm glad someone else asked! Has anyone been able to find out if either the IRMA Fastlink board (which uses some bizarre packetization scheme) or Racal-Vadic's new 9600 baud modem can handle uucp. How about "layers" (the protocol for the TTY 5620 "Blit")? Thanks -- ## Bill Stewart, AT&T Bell Labs, Holmdel NJ 1-201-949-0705 ihnp4!ho95c!wcs ------------------------------ Date: Sat, 26 Oct 85 14:18:43 pdt From: newton%cit-vlsi@cit-vax.ARPA (Mike Newton) Subject: Data Access Lines Another fine point in the Pacific Bell flyer regarding their new data service was a section saying they would no longer respond to complaints from non-Data-Access-Line customers regarding data transmission quality. -mike ------------------------------ Date: Sun, 27 Oct 85 12:48 EST From: "Richard Kovalcik, Jr." <Kovalcik@MIT-MULTICS.ARPA> Subject: dialing 617 460 .... Well, at least you could do it by busying out the FX line. I have some friends who work for companines in Boston that absolutely can't call me at 617-460-2206 because their STUPID office PBX doesn't understand the 460 exchange and consequently blocks all calls to it. Fortunately after several weeks most companines can get this straightened out. ------------------------------ Date: Fri, 25 Oct 85 23:58:58 PDT From: ihnp4!homxb!hrs@UCB-VAX.Berkeley.EDU Subject: Re: TELECOM Digest V5 #54 Re: Call guide to Washington DC. Some interesting facts about (202) 693-xxxx The 693 exchange for the Defense Department in Virginia, i.e. the Pentagon, which is in the 202 area code, is actually a 1A ESS located in the Pentagon. While it is totally dedicated to one customers and located on customer premises, it is still considered a network switch, and is owned by C&P. It is a Centrex dedicated to one customer and used as a PBX. Its is one of the largest 1A's around. Herman Silbiger ihnp4!homxb!hrs ------------------------------ End of TELECOM Digest *********************