From: davidsen@sixhub.UUCP (Wm E. Davidsen Jr) Subject: Re: 38400 or 57600 baud, which to use? With what FIFO trigger setting? Date: 8 Aug 1993 23:46:58 GMT
In article <17045@rand.org> edhall@rand.org (Ed Hall) writes:
| You are ignoring the effect of start and stop bit deletion. Raw V.42
| throughput (no compression) is about 17200 bits/second as measured at
| your computer's serial port (14400 * 10/8 == 18000, minus overhead).
| So a compression ratio of about 2.23 to 1 is enough to saturate a
| 38400bps asyncronous connection. I've seen V.42bis give better compression
| than this for ordinary English text, and 3 to 1 for things like C
| sourcecode.
This is an important point! Even on non-compressable data the V.42
brings the speed up to about 18k and lowly V.32 (non-bis) up to 12k
(both ignoring overhead). People who calculate using ten bits/byte often
wonder how their computer can do so well with data transfer!
--
Bill Davidsen, davidsen%sixhub.uucp@uunet.uu.net
TMR Associates, +1 518-370-5654
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