Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!rochester!cornell!batcomputer!pyramid!octopus!pete From: pete@octopus.UUCP Newsgroups: comp.dcom.modems Subject: Re: Looking for a fast modem < $1000. Message-ID: <371@octopus.UUCP> Date: Mon, 7-Dec-87 14:16:43 EST Article-I.D.: octopus.371 Posted: Mon Dec 7 14:16:43 1987 Date-Received: Sat, 12-Dec-87 19:00:50 EST References: <48400001@uxe.cso.uiuc.edu> <7753@g.ms.uky.edu> <8093@ism780c.UUCP> <7826@g.ms.uky.edu> Reply-To: pete@octopus.UUCP (Pete Holzmann) Organization: Octopus Enterprises, Cupertino, CA Lines: 35 Summary: Telebit falls back in 2bps increments In article <7826@g.ms.uky.edu> david@ms.uky.edu (David Herron -- Resident E-mail Hack) writes: >In article <8093@ism780c.UUCP> tim@ism780c.UUCP (Tim Smith) writes: >>I seem to recall that the proposed standards ( e.g., from ISO ) suck. >>They do things like fall back from 9600 to 4800 if there is too much >>line noise. The Trailblazer is much better. > >The trailblazer will fall back as well, but in 300 baud speed increments >instead of 4800 baud increments. > Unless I am mistaken, the trailblazer falls back in 17.5 bps increments; at least, that's what the transmit/receive bits-per-channel reports indicate. For those of you who haven't yet joined the ranks of happy users: the modem has several reports available if you inquire the value of certain S-registers. Two of these show, for each of 511 bands spaced 7.8 Hz apart, how many bits are being sent or received in each band. The number of bits/band adjusts as a value in the set (0,2,4,6) individually for each band. If you compare these numbers with the instantaneous transmit/receive rate (available in another S-register), you find that a change of 2 in a single band corresponds to approximately 17.5 bps change in the data rate. Note that since the modem performs buffered data rate translation, there is no need for the host CPU to know any of these details: on a bad line, the data throughput just goes down! In case you're wondering what kind of modem would have detailed reports like this... that's only the beginning. There's even a report that shows line noise level in each of the 512 bands in dBm to the nearest tenth! This thing could probably be reprogrammed to be a nice signal analyzer. Disclaimer: Just another (very) satisfied customer. -- OOO __| ___ Peter Holzmann, Octopus Enterprises OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete ___| \_____ Phone: 408/996-7746