[Coco] Re: Supercomm: more details

KnudsenMJ at aol.com KnudsenMJ at aol.com
Mon Aug 16 22:39:00 EDT 2004


In a message dated 8/15/04 11:40:14 PM Eastern Daylight Time, wb8tyw at qsl.net 
writes:

> A host computer is supposed to treat a loss of DCD or DSR as the 
>  termination of the serial session.

Yes, you're right -- loss of DCD should cause a computer to "log out" that 
session, and the modem relay goes "click" and hangs up the phone.  My bad.

There really isn't any signal to tell either end that valid data are now 
coming in, and there really isn't any need to -- as long as the data input lead 
idles in the "mark" level, no data bits are coming in.  That's the beauty of 
asynchronous serila transmission -- hasn't changed since the early Teletype 
machines.  --Mike K.



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