Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!rutgers!mcnc!ecsvax!taylor From: taylor@ecsvax.UUCP (Steven Taylor) Newsgroups: comp.dcom.modems Subject: Re: 9600 baud standards Message-ID: <3870@ecsvax.UUCP> Date: Wed, 16-Sep-87 11:58:35 EDT Article-I.D.: ecsvax.3870 Posted: Wed Sep 16 11:58:35 1987 Date-Received: Thu, 24-Sep-87 04:28:15 EDT References: <171@tahoma.ARPA> Organization: UNC Educational Computing Service Lines: 36 Summary: problems with 9600 bps modems on compressed voice There is an additional problem with any 9600 bps dial-up modem. Many organizations are now converting their internal voice transmission systems to T-1 based systems using compressed voice. Unfortunately, virtually none of the compressed voice algorithms support 9600 bps modem transmission. The systems are fine for voice, but modems, especially those at high speeds, use the available spectrum very differently than "normal" voice. A handful of manufacturers have some specialized techniques to allow V.29 transmission with digital voice at 32 kbps (standard telco uses 64 kbps PCM), but these are proprietary to each vendor. I haven't heard of any which support V.32. This is a MAJOR problem for systems designers. With systems offering up to 10 to 1 compression over the telco standards, it's hard to avoid using compression of voice. However, it does cause this problem for "normal" modem use. As we approach an "all digital world," this could be a major stumbling block within many organizations, so, personally, I am not too sure what the future of the high speed modems will be. I guess it depends a lot on the extent to which the digital services are extended, and at what speeds. For a related problem with V.32 and use on "OCC's" (not AT&T), see the news item in the September "Data Communications" magazine, page 15. (Is this the appropriate newsgroup for ISDN discussions? I've been off the net for a while, so I'm not sure. Thanks.) Steve Taylor Distributed Networking Associates Greensboro, NC 919-292-4444