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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!gem.mps.ohio-state.edu!ginosko!uunet!bulus3!haugen
From: haugen@bulus3.BMA.COM (John M. Haugen)
Newsgroups: comp.dcom.modems,comp.unix.xenix
Subject: Re: Trouble with TB Plus (Please Help!!)
Keywords: TB+, UUCP, Xenix
Message-ID: <210@bulus3.BMA.COM>
Date: 23 Aug 89 14:15:04 GMT
References: <124@clleth.UUCP>
Followup-To: poster
Organization: Bull Micral, Roseville, MN
Lines: 33

In article <124@clleth.UUCP>, grant@clleth.UUCP (Grant Fengstad) writes:
> I am having some wierd problems with my Telebit Trailblazer Plus modem.
> ...
> The modem is connected into the standard port (9 pin RS-232C).  The problem
> I am experiencing is with Netnews transfers.  At the 19,200 baud speed,
> uucico is reporting transmission faults from my host feed.  My effective
> transfer rate sucks, to put it bluntly.  What is happening is as news
> is being queued to transfer, the modem appears to time out and reports
>  Alarm 1
>  Alarm 2
>  Alarm 3, etc etc.
> 
> If I kick the modem speed down to 9600 via my Systems file, it transfers 
> without any errors.

I had similar problems with my system (PS2 class machine running ISC 386/ix)
and found out the problem was the device driver of the serial port could not
keep up with the data stream at the higher speeds.  Incoming characters were
lost because the OS could not respond fast enough.  

My fixed was to obtain a serial driver from Jim Murray (jjm%jjmhome@m2c.m2c.org)
that took advantage of the builtin FIFO in the UART chip (16550) in my 
machine.  Since adding that device driver, I have not had any more problems
with alarms during uucico xfers even at 19200 baud rate.  I have been told
that Interactive Systems (maker of 386/ix) is working on an upgrade of there
serial device driver to handle some of these problems.

Hope this helps

John M. Haugen             Domain:  haugen@BMA.COM
Bull Micral of America     UUCP:    ...!uunet!bulus3!haugen
1970 Oakcrest Ave. #300    ATT:  612-633-5660
St. Paul, MN  55113-2624