Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!sri-spam!sri-unix!hplabs!pesnta!altos86!grinch!jason From: jason@grinch.UUCP (jason) Newsgroups: comp.dcom.modems Subject: Re: An interesting modem problem Message-ID: <184@grinch.grinch.UUCP> Date: Mon, 17-Nov-86 19:16:14 EST Article-I.D.: grinch.184 Posted: Mon Nov 17 19:16:14 1986 Date-Received: Tue, 18-Nov-86 22:03:02 EST References: <128@gaia.UUCP> <133@gaia.UUCP> Reply-To: jason@grinch.UUCP Organization: Textural Software, San Jose, CA. Lines: 39 In article <133@gaia.UUCP> zhahai@gaia.UUCP (Zhahai Stewart) writes: >Some more possibly useful information on the ~r and }i modem problem: >One modem is a Hayes 1200 which has had no similar problem in connecting >to many other modems over the last couple of years. The other is a >2400 bps modem, operating at 1200 of course, which has not had the same >problem with anyone else. [....] > >Thoughts: it *might* have to do with adaptive equalization on the 2400 >bps side, with some phone connections. It might have to do with losing >sync in the pseudo random scramblers used with 1200 bps. > > Zhahai Stewart HiSystems > nbires!gaia!zhahai (WARNING: I am new to the net, and it's been awhile since I worked on this, so, please.. not TOO many flames!!) Aside from that... I might have SOME info for you.. I had been evaluating 2400 baud modems for my old company, and I have found what seems to be an oversight from Rockwell... Seems the chip set marked version 'G' (for the reciever only, the transmitter is fine) does not (at 1200 baud) support the modulation envelope that they use to try and reduce line noise and impedance matching. Rumor has it that they didn't think it was necessary.... If you think that is the problem (i.e, you have the 'G' reciever chip) then what you need to do is get the reciever chip version 'J' from your favorite modem dealer (or, probably just call Rockwell and complain) and that should clear up most of your problems. Hope this helps!! Jason Of course, if you don't have a modem with the Rockwell chips sets.... "Never mind...." ...!sun!altos86!grinch!jason Disclaimer?? Naaaa..... Who would listen to me anyway??