Path: utzoo!attcan!uunet!sdrc!thor!scjones
From: scjones@thor.UUCP (Larry Jones)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Baud vs. bps.
Message-ID: <142@thor.UUCP>
Date: 27 Aug 90 13:17:11 GMT
References: <849@idcapd.idca.tds.philips.nl> <4188@trantor.harris-atd.com> <5001@pegasus.ATT.COM>
Organization: SDRC, Cincinnati
Lines: 26

In article <5001@pegasus.ATT.COM>, dmt@pegasus.ATT.COM (Dave Tutelman) writes:
> A "bit" is a unit of information.  Start and stop pulses (frequently
> and inaccurately called start and stop bits) are really transmission
> related synchronizing signals, not information.  The "old" modems
> Bob describes actually had a bit rate LESS than the baud rate.

Well, everything's relative, but I have to disagree with you
here.  A modem converts a serial bit stream into a signal
suitable for transmission over a phone line and vice versa. 
The start and stop "pulses" ARE, in fact, BITS in the serial bit
stream -- the modem doesn't have to do anything special with
them, it just transmits them like any other bits.

Thus, they should be counted when calculating the bps rate.  (And
as far as I know, they always are.  I've never heard anyone refer
to a modem as being 1200 bps synchronous, 960 bps async).  Of
course, they DO make a difference when calculating the characters
per second rate, which is why cps isn't simply bps / 8 that you
might expect.  But that's a function of serial communication,
whether modems are involved or not.
----
Larry Jones                         UUCP: uunet!sdrc!thor!scjones
SDRC                                      scjones@thor.UUCP
2000 Eastman Dr.                    BIX:  ltl
Milford, OH  45150-2789             AT&T: (513) 576-2070
Bad news, Mom.  I promised my soul to the Devil this afternoon. -- Calvin