Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!sun-barr!lll-winken!scooter!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.sys.att
Subject: Re: 19200 baud on the Unix PC serial port
Summary: EXTA, EXTB
Message-ID: <1865@neoucom.UUCP>
Date: 30 Dec 89 21:30:50 GMT
References: <1861@neoucom.UUCP> <5272@eagle.wesleyan.edu>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 13


Actually, the token for 19200 bps is "EXTA".  I believe that comes
from the DRV-11 (or something similar) on the PDP-11 that supported
two _external_ clock rates, which were supposed to have been
supplied from a clock generator in the modem.  The DRV-11 is a
single line serial RS-232C or current loop interface.

If you look in /usr/include/sys/termio.h, you'll see both EXTA and
EXTB defined.  EXTB is not suppoted by the kernel, according to a
comment in termio.h; if EXTB worked, it would be for 38400 bps.


Bill