zero modem connector

elektor electronics november 1985 zero- conn by J Steeman Fig.1 A number of poss- ible connections between two RS232 connectors. There is probably no other interface that gives so many problems as the RS232. Quite a few connecting wires are needed to ensure the correct links for all possible applications. The reason for this lies in the number of possible handshakes pertaining to the RS232 protocol. With modern equip- ment, many of these handshakes are no longer strictly necessary, so that a much simpler connection will suffice. At the same time, many idiosyncrasies of various com- puter manufacturers can be circumvented. The zero-modem connector proposed is based on the idea of reducing the hand- shakes. Each equipment provides its own handshake, while the connector looks after the interconnections of the data lines. There is then, of course, no longer any control between the individual units, but there is a correct data link. C TEL R x0 RTS CIS OCR DCD GND 174-1:5 RTS CTS the ze...