storm@cs.mcgill.ca (Marc WANDSCHNEIDER) (03/07/91)
What is the difference between V.32 and V.32bis...? Is V.32bis a
transfer protocol as is V.32, or is it something else...?
What sort of throughput can one expect (theoretically I suppse) using a
V.32bis modem with V.42bis compression...?
./*-
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
storm@cs.mcgill.ca McGill University It's 11pm, do YOU
Marc Wandschneider Montreal, CANADA know what time it is?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~tnixon@hayes.uucp (03/07/91)
In article <1991Mar6.165542.10140@cs.mcgill.ca>, storm@cs.mcgill.ca (Marc WANDSCHNEIDER) writes: > What is the difference between V.32 and V.32bis...? Is V.32bis a > transfer protocol as is V.32, or is it something else...? V.32 provides full-duplex, async or sync transmission at 4800 and 9600bps on two-wire dial-up or leased lines. To change speeds, you must retrain the modems, which takes five to ten seconds. V.32bis provides full-duplex, async or sync transmission at 4800, 7200, 9600, 12000, and 14400bps on two-wire dial-up or leased lines. It is backward-compatible with V.32. In addition to the retrain mechanism for speed changes, V.32bis also provides a "rapid rate renegotiation" capability, which allows the modems (if mutually agreeable) to change rates up or down in about 1/10th of a second. > What sort of throughput can one expect (theoretically I suppse) using a > V.32bis modem with V.42bis compression...? If you accept that V.42bis achieves up to 4-to-1 compression on text data, you could expect to see up to 57,600bps throughput with V.42bis over V.32bis. This is quite dependent on the modem implementation. Many vendors are sticking with a maximum 38,400bps interface rate, and using the increased modulation speed of V.32bis to increase the types of data that actually acheive 38,400bps throughput, rather than trying to push for more. V.32bis also increases the throughput of uncompressible data and of synchronous transmissions. -- Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net
gklaass@yunexus.yorku.ca (Gary Klaassen) (03/08/91)
>V.32bis provides full-duplex, async or sync transmission at 4800, >7200, 9600, 12000, and 14400bps on two-wire dial-up or leased lines. >-- >Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 >Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 I remember seeing a notice that the V.32bis standard was due to be ratified on March 1, but I have seen nothing since. Has the V.32bis standard already been frozen? If not, can anyone give us a probable date? Thanks, Gary Klaassen, Dept. Earth and Atmospheric Science, York University G. Klaassen Associate Professor Dept. of Earth and Atmospheric Science York University