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From: splee@pogo.gnu.ai.mit.edu (Seng-Poh Lee, Speedy)
Newsgroups: comp.dcom.modems
Subject: Re: 2400/MNP5/V.42bis and flow control
Message-ID: <15358@life.ai.mit.edu>
Date: 27 Apr 91 17:11:26 GMT
References: <1991Apr27.072711.6600@wimsey.bc.ca>
Sender: news@ai.mit.edu
Organization: FSF Guest Machines
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In article <1991Apr27.072711.6600@wimsey.bc.ca> sl@wimsey.bc.ca (Stuart Lynne) writes:
>I'm considering replacing my old 2400 bps modems with new 2400 bps with MNP5 
>and V.42bis modems for my low speed interactive users. 
>
>The problem I have is that the Equinox card I have does not (easily) support
>hardware flow control. Is it easy to use make effective use of these modems
>by locking the interface at 4800 bps?
>
>The problem as I understand it is trying to use file transfer programs (uucp,
>[xyz]modem, kermit) to send compressed files. Is there any work around other
>than using hardware flow control?
>
This has been a problem with MNP modems, where you always want to run the DTE
speed faster than the modem. However, this is hard to do without hardflow
control. THe only hope you have is that whatever protocol you use requires
an ack before the buffer in your MNP modem fills up. If your buffer is big
enough, you can get away with x,ymodem, and kermit. However you have to
run zmodem in a non-streaming mode i.i; requires ack. Also you have to make
sure you disable the xon/xoff flow control as well. Try and get a modem
which has at LEAST 4K of outgoing MNP buffer. And yes, you would lock your
DTE rate to 4800 or higher. Hopefully the modems you buy will do speed 
buffering if a user calls in without MNP. THey should.


--
Seng-Poh Lee
splee@gnu.ai.mit.edu