Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!midway!oddjob!rfl
From: rfl@oddjob.uchicago.edu (Bob Loewenstein)
Newsgroups: comp.sys.mac.comm
Subject: serial problem
Message-ID: <1990Oct30.174825.25138@midway.uchicago.edu>
Date: 30 Oct 90 17:48:25 GMT
Sender: news@midway.uchicago.edu (News Administrator)
Reply-To: rfl@oddjob.uchicago.edu (Bob Loewenstein)
Organization: U of Chicago - Astronomy & Astrophysics
Lines: 13


I have been using the serial port on the mac for years with no problem. I now
have a problem using a high speed modem (Microcom v.32c and also v.42bis) at
MNP7 and MNP10 protocols. The baudrate between the mac and the modem is 38400.
The remote modem is connected to a Sun also at 38400. The problem is that every
so often (about 1/60000 bytes) I get a -89 error (SCC receiver error, framing,
parity..) from the serial driver IOResult. I have tested with both DTR hardware
handshaking and no handshaking with the same results.

The problem does not happen at baudrates less than 38400.

Anyone have any ideas? A while back I tested mac <-> mac communications at 38400
and 57600 baudrates (no modem in between) and did not see these errors.