Message-ID: <361@ahuta.UUCP>
Date: Tue, 15-Jan-85 07:51:46 EST
Article-I.D.: ahuta.361
Posted: Tue Jan 15 07:51:46 1985
Date-Received: Wed, 16-Jan-85 05:24:39 EST
References: <816@pucc-i>
Organization: AT&T Information Systems Labs, Holmdel NJ
Lines: 23
REFERENCES: <816@pucc-i>
Thanks for posting the pin assignments. I'd like to make one small
correction, not in the pins but the terminology. A "null modem cable"
is NOT a modem cable without control leads. It's a cable that
REPLACES a modem, so that two back-to-back terminals (or terminal
and computer) can converse without benefit of a modem.
For example:
Transmit data ------------------------------ Receive data
Receive data ------------------------------ Transmit data
Request to send ------------------------------ Clear to send
Clear to send ------------------------------ Request to send
Modem ready ------------------------------ Terminal ready
Terminal ready ------------------------------ Modem ready
Ground ------------------------------ Ground
is an example of a null modem with some control leads implemented.
Note the transposition of leads (Transmit to Receive & vice-versa)
that is the characteristic of null modems.
Dave Tutelman