Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!cornell!uw-beaver!tektronix!uunet!portal!cup.portal.com!mhyman
From: mhyman@cup.portal.com
Newsgroups: comp.dcom.modems
Subject: Re: Break definition
Message-ID: <9206@cup.portal.com>
Date: 17 Sep 88 21:34:29 GMT
References: <402@ucrmath.UUCP> <248@lakart.UUCP>
Organization: The Portal System (TM)
Lines: 22
XPortal-User-Id: 1.1001.2549

In article <248@lakart.UUCP> dg@lakart.UUCP (David Goodenough) asks:
> break a lot of things for me. For example I call in 7e1 to talk text
> with lakart, but if I'm going to do an Xmodem transfer, I have to set
> my end to 8n2 to get it to go. Now if the modem is hooked on the notion
> of 7e1, I'm in real trouble. How are other people getting around this, ...

At 300 bps the modem encodes 1 bit per baud; when the signal at the RS-232
port changes the modem sends a different frequency.  That's why modems
are rated 0-300 bps.  At the higher frequencies multiple bits are encoded
per baud.  The modem needs to know the character size (but not the parity)
so it may drop a stop bit when needed.  The receiving modem needs to know
the character size so it can tell when it has to insert a stop bit. 

Most modems these days assume a character size of 10 bits.  If you look
at a Smartmodem 2400 manual (page A25) you'll see that all supported
Asynchronous data formats add up to 10 bit characters.

--Marc

Marco S. Hyman
...!sun!portal!cup.portal.com!mhyman
mhyman@cup.portal.com