DEC MMJ

pinout

MMJ=Modified Modular Jack. Invented by Digital Equipment Corporation (DEC) (now: Compaq)

6 pin MMJ female connector  at the devices

Pin Name Description 1 DTR Data Terminal Ready 2 TXD+ Transmit Data + 3 TXD- Transmit Data - 4 RXD- Receive Data - 5 RXD+ Receive Data + 6 DSR Data Set Ready

6 pin MMJ male connector  at the cables

Source:www.pinouts.ru