Date   : Fri, 04 Oct 1985 09:22:27 EDT
From   : David Towson (SECAD) <towson@AMSAA.ARPA>
Subject: Re: 7000+ character tutorial on sending BREAK:

Fellow CP/Mers - I received the following note in response to my recently
posted tutorial on sending BREAK over serial asynchronous links:

       From: (Richard Kenner) <KENNER@NYU-CMCL1.ARPA>
       To: <towson@AMSAA.ARPA>
       Subject: RE: 7000+ character tutorial on sending BREAK:
       
       Minor correction to your very good lesson on asynch for those who
       believe the world started with the microcomputer:  The convention as
       I have always heard it is to default to 2 stop bits for baud rates
       150 and below, not 110 and below.  In field test versions of some DEC
       operating system (I think RSX, but am not sure), they also originally
       had 110 and changed it to 150 when I reported it to them.
       
     Thanks, Richard.  Anybody know what hardware was originally responsible
for the use of 150 baud?  110 baud was derived from a nominal rate of 10
characters-per-second, with 11 bits (one start, eight data and two stop) per
character (10 x 11 = 110).  150 baud appears to be based on 15 characters-per-
second with 10 bits (only one stop-bit) per character.  Who made the first 15
cps printer?


Dave