[Ethernet AUI] [MMJ Serial] [Mouse] [Keyboard] [Video] [SCSI50] [SCSI68] [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 carl.friend@stoneweb.com and
woferry@warpdrive.res.cmu.edu 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
1-12 GND
13 No Connection
14-25 GND
26-33 Data0-Data7
34 Data Parity
35 GND
36 GND
37 Reserved(GND for single ended)
38 Terminator Power
39 Reserved
40 GND
41 -ATN
42 GND
43 -BSY
44 -ACK
45 -RST
46 -MSG
47 -SEL
48 -C/D
49 -REQ (for SCSI2, GND for DS3100)
50 -I/O
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, and it's also male...
Taken from http://ce.et.tudelft.nl/~knop/cables/DEC_SCSI.html without permission as the old page is now dead.
The DEC connector has 68 pins in two rows of 34. Distance between the rows is probably 0.1", distance between adjacent contacts in a row is probably 0.05". The connector on the cable is female. There is a trapezoid shell around the contacts that extends about 0.2". This is probably an AMP type 174731-5 connector.
View on cable end of connector (NOT on contact end):
______________________________________ \ .................................. / \................................../ __________________________________ (arbitrary) contactnumbering: 1................................34 35................................68
The Centronics type connector has a similar shape, but is much bigger. This connector resembles the "CHAMP" connector system in the AMP catalogue. It has 50 contacts in two rows of 25. The connector on the cable is male.
View on the cable side of the connector:
_____________________________ \ ......................... / \........................./ _________________________ (arbitrary) contactnumbering: 1 25 26 50
DECstation CHAMP DECstation CHAMP
1 NC 35 NC
2 NC 36 NC
3 NC 37 37
4 NC 38 NC
5 1 39 NC
6 38 40 NC
7 26 41 NC
8 27 42 NC
9 28 43 6
10 29 44 NC
11 30 45 NC
12 31 46 NC
13 7 47 2
14 32 48 NC
15 33 49 NC
16 35 50 NC
17 42 51 NC
18 17 52 NC
19 43 53 NC
20 18 54 NC
21 44 55 4
22 19 56 NC
23 45 57 5
24 20 58 NC
25 46 59 NC
26 21 60 NC
27 47 61 3
28 22 62 NC
29 48 63 8
30 23 64 NC
31 49 65 NC
32 24 66 NC
33 50 67 10
34 25 68 NC
As a check the same cable seen from the other side:
CHAMP DECstation CHAMP DECstation
1 5 26 7
2 47 27 8
3 61 28 9
4 55 29 10
5 57 30 11
6 43 31 12
7 13 32 14
8 63 33 15
9 NC 34 NC
10 67 35 16
11 NC 36 NC
12 NC 37 37
13 NC 38 6
14 NC 39 NC
15 NC 40 NC
16 NC 41 NC
17 18 42 17
18 20 43 19
19 22 44 21
20 24 45 23
21 26 46 25
22 28 47 27
23 30 48 29
24 32 49 31
25 34 50 33
Use a cable with shielding (connected to the metal trapezoid shield
of the connectors).
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.