PDP 11/03

Johnny Billquist bqt at update.uu.se
Tue Nov 10 07:06:47 CST 2015

On 2015-11-10 11:55, Christian Corti wrote:
> On Mon, 9 Nov 2015, Johnny Billquist wrote:
>> Normally, you'd call them Tx, Rx and GND, but anyway...
>> No, you do not need to loop back any signals. DEC didn't like to abuse
>> modem control for flow control.
> What about the connections between the TTL signals and the line
> drivers/receivers? There are definitley such connections to be made in
> the Berg connector (like TTL SERIAL DATA IN on connector pin E). For EIA
> you need to connect pin E with pin M. (See also page 178 in the
> microcomputer interfaces handbook [1980]).

Yes. The signals exist, because you might be connecting to a modem. But 
they are not used for flow control. You can control what is output, and 
you can check what comes in. But the hardware do not act on any of this.
If you write your own software then you can of course do things based on 
those signals...


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