[Ethernet AUI] [MMJ Serial] [Mouse] [Keyboard] [Video] [SCSI] [Other References] [back]
1. control in circuit shield
2. control in circuit A
3. data out circuit A
4. data in circuit shield
5. data in circuit A
6. voltage common
7. x nc
8. control out circuit shield
9. control in circuit B
10. data out circuit B
11. data out circuit shield
12. data in circuit B
13. voltage plus
14. voltage shield
15. x nc
shell. protective ground
Note: There's a recessed pushbutton switch between the ethernet connectors marked # that selects between the AUI and the internal 10base2 transceiver. A LED is lit next to the connector that is enabled.
Corresponding 25 pin RS-232 pins as a DTE device (you need a null modem to
hook this up to a terminal.)
Here you can connect as a DCE device.
There are two MMJ serial ports on the DECstation 3100. The PRINTER port has no
handshaking pins (pin 1 and 6 are NC) and defaults to 9600bps. The MODEM port
has the handshaking signals and defaults to 1200bps. In either case you
only need to connect pins 2 through 5 and ignore hardware handshaking to get
bits to pass.
Pin Function DB25 DB9 Null-DB25 Null-DB9 1. DTR -> 20 4 6 6 2. TD (+) -> 2 3 3 2 3. TD (-) -> 7 5 7 5 4. RD (-) -> 7 5 7 5 5. RD (+) -> 3 2 2 3 6. DSR -> 6 6 20 4
+ 5 6 7 3 4 +1 2+
(Direct view of back of system unit.) Likely this isn't too useful unless you
find a keyboard with its plug ripped off or if you want to make a null
keyboard (hook up TXD to RXD).
+-------+ 1. TXD - transmit to keyboard |1 2 3 4| 2. signal GND +--+ +--+ 3. +12V to power keyboard +-+ 4. RXD - receive from keyboard
Pinout for video - Probably the most requested pinout on this page. Likely
this is because that funny cable that DEC made is most likely lost in
transit. :-) I leave mine attached to the monitor to make sure I never
lose the darned thing. Of course, if I lose the monitor, then I'd be in a
world of hurt. I guess it doesn't really matter at that point anyway...
DB15 connector, male (not HD15 like PC VGA)
1. Red video output
2. Color Ground Common
3. Monochrome Ground
4. Mouse pin 7
5. Mouse pin 1
6. Keyboard pin 2
7. Mouse pin 2
8. Keyboard pin 3
9. Monochrome output (functions as green too) (Synchronization on this pin)
10. Green video output (H/V Composite Synchronization on this green pin)
11. Blue video output
12. Mouse pin 3
13. Mouse pin 4
14. Keyboard pin 4
15. Keyboard pin 1
This is supposed to be RS343A/RS170 compatible... Also the keyboard and mouse pins don't work on the DS 2100/3100. Supposedly they're for the VaxStation 3100 and later models (DS 5000). Thanks to firstname.lastname@example.org and email@example.com for probing their cables.
The internal connector is a single ended SCSI-1 connector, 50 pins. The external one that's 68 pins is custom.
Connector:50 pin Centronics at end of external SCSI cable and internal
50 pin IDC header
13 No Connection
34 Data Parity
37 Reserved(GND for single ended)
38 Terminator Power
49 -REQ (for SCSI2, GND for DS3100)
The unusual 68-pin male connector on the rear of the machine looks like a wide scsi interface, however, the box does not have a wide scsi host controller. Its pinout is not that of a regular wide scsi 68-pin connector.
Wow, someone who probed his cable has a page here. Look here for pinout of the Honda/AMP68 Male pmax SCSI
Warning! You must have the terminator plugged into the back of the machine if you have no external peripherals. Sometimes you can get away with it though, my machine seems to work fine without it but the SCSI chain is nowhere in spec like this. Your mileage and DATA INTEGRITY may vary. The SCSI bus is terminated on the motherboard and at least my pmax, it's impossible to remove the termination as it's solderred onto the board.