parnass@ihuxf.UUCP (01/19/84)
x
Folks always seem to confuse "bits per second" (bps) with
"baud." Some related information:
a. Baud is a unit of signaling rate, and already contains
units of time. Talking of "baud rates" makes about as
sense as talking about "knot rates."
b. Baud is its own plural, hence there is no such word as
"bauds."
c. The signaling rate of most 1200 bps modems on the DDD
telephone network is not 1200 baud. Combinations of
phase and/or amplitude modulation can be employed to
send data at 1200 bps using a signaling rate of 300 or
600 baud.1 Here, the information rate (bps) > signal-
ing rate (baud).
d. If you still need convincing that bps != baud, then
examine the timing diagram of the 7.42 unit code used
by Teletype 33 and 43 teleprinters. The stop and
start pulses are of different lengths. In this case,
the information rate (bps) < signaling rate (baud).
__________
1. I won't present the details of any one particular model
modem. This is the kind of information that companies
like to classify as proprietary.
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Robert S. Parnass, AT&T Bell Laboratories, ihnp4!ihuxf!parnass (312)979-5760 ron%brl-vgr@sri-unix.UUCP (01/22/84)
From: Ron Natalie <ron@brl-vgr> Thank you, I was getting rather sick of seeing the word "bauds." Most people refer to 1200 Baud modems as such because it can take 1200 (really) baud modems and transfer them over the phone line (at 1200 bps). Most people understand RS232 and the interface between the modem and TPC is a black art. -Ron