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From: bender@oobleck.Eng.Sun.COM (Michael Bender)
Newsgroups: sci.electronics
Subject: Re: RS232 Flow Control
Message-ID: <2489@exodus.Eng.Sun.COM>
Date: 10 Nov 90 02:16:23 GMT
References: <1990Nov10.013730.28838@julius.cs.uiuc.edu>
Sender: news@exodus.Eng.Sun.COM
Organization: Sun Microsystems, Mt. View, Ca.
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In article <1990Nov10.013730.28838@julius.cs.uiuc.edu> totty@flute.cs.uiuc.edu (Brian Totty) writes:
>
>	I want to send flow control information back to a sender across
>	an RS232 serial cable.  What signal is appropriate for this?
>	Do I use CTS (clear to send), or one of these "secondary" signal
>	lines?  All I want to do is to be able to temporarily tell the sender
>	not to send my UART data is some relatively standard way.  I am
>	using a direct null-modem connection and can get a full 25 pin
>	cable.

I've used CTS/RTS.  My computer monitors CTS, and when it goes low, the
data transfer from my system is paused, until CTS goes high again.  RTS
is asserted normally, and when my system detects it's input buffers
getting full, is deasserts RTS.

mike
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