DEC MMJ Serial Connector Pinout
From AllPinouts
Connector pinout for: DEC MMJ Serial
6 pin MMJ female connector at the devices.
6 pin MMJ male connector at the cables.
| 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 |
Hints
A common task is to build an adaptor to RS-232 using the DB-25 or DE-9 plug on the one side (to be connected to a PC) and the MMJ connector on the other. Though serial transmission is done with differential voltage, it's actually quite easy. Simply connect MMJ pins 3 and 4 to the DB-25 / DE-9 GND pin, then use MMJ pins 2 and 5 as regular TX/RX pins (to be connected to pins 2 and 3 on the DB-25 / DE-9 side, depending on whether to build a direct crossed console cable or just an adaptor. You can also connect pins 1 and 6, but I'm not exactly sure where. For a plain console cable, they are not necessarily needed.
References
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