Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.PCS 1/10/84; site ahuta.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!houxm!ahuta!dmt From: dmt@ahuta.UUCP (d.tutelman) Newsgroups: net.micro.pc Subject: Re: Homemade AT Serial Port/RS232 Cable - (nf) 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