IBM SCSI Pinouts

IBM SCSI External Connectors & Cables

Internal 50-pin Card-Edge Connector
Internal 50-pin Header Connector
External 60-pin Connector
Internal/External 68-pin Connector
External 50-pin Connector
Sources


Internal 50-pin Card-Edge Connector

Used on most IBM SCSI adapters to connect internal devices (narrow; 8-bit).

PinSignalPinSignal
1Ground2-Data 0
3Ground4-Data 1
5Ground6-Data 2
7Ground8-Data 3
9Ground10-Data 4
11Ground12-Data 5
13Ground14-Data 6
15Ground16-Data 7
17Ground18-Data Parity
19Ground20Ground
21Ground22Ground
23Ground24Ground
25Not Connected26+Terminal Power
27Ground28Ground
29Ground30Ground
31Ground32-Attention
33Ground34Ground
35Ground36-Busy
37Ground38-Acknowledge
39Ground40-Reset
41Ground42-Message
43Ground44-Select
45Ground46-Control/Data
47Ground48-Request
49Ground50-Input/Output

Pin 1 is located on the solder side of the PCB, closer to the rear metal bracket.

There is a physical key between pins 25 and 27 (26 and 28).

On the "Tribble" PCB the odd pins 1-49 are marked as BB01-BB25 (solder side) and even pins 2-50 as AA01-AA25 (component side).


Internal 50-pin Header Connector

This is the "industry standard" internal SCSI connector (narrow; 8-bit). It's used by all planar SCSI implementations and also by the following adapters:

PinSignalPinSignal
1Ground2-Data 0
3Ground4-Data 1
5Ground6-Data 2
7Ground8-Data 3
9Ground10-Data 4
11Ground12-Data 5
13Ground14-Data 6
15Ground16-Data 7
17Ground18-Data Parity
19Ground20Ground
21Ground22Ground
23Ground24Ground
25Not Connected26+Terminal power
27Ground28Ground
29Ground30Ground
31Ground32-Attention
33Ground34Ground
35Ground36-Busy
37Ground38-Acknowledge
39Ground40-Reset
41Ground42-Message
43Ground44-Select
45Ground46-Control/Data
47Ground48-Request
49Ground50-Input/Output


External 60-pin Connector

60-pin Mini Centronics

This is the 60-pin Mini Centronics connector used on most narrow IBM SCSI adapters to connect external devices.

PinSignalPinSignal
1Ground31Ground
2-Data 032-Attention
3Ground33Ground
4-Data 134Ground
5Ground35Ground
6-Data 236-Busy
7Ground37Ground
8-Data 338-Acknowledge
9Ground39Ground
10-Data 440-Reset
11Ground41Ground
12-Data 542-Message
13Ground43Ground
14-Data 644-Select
15Ground45Ground
16-Data 746-Control/Data
17Ground47Ground
18-Data Parity48-Request
19Ground49Ground
20Ground50-Input/Output
21Ground51Ground
22Ground52Reserved / Ground**
23Ground53Reserved / Ground**
24Ground54Reserved / Ground**
25Not Connected55Reserved / Ground**
26+Terminal Power (+5 V fused)56Reserved / Ground**
27Ground57Reserved / Ground**
28Ground58Reserved / Ground* / Ground**
29Ground59Reserved / 8032 RXD* / Ground**
30Ground60Reserved / 8032 TXD* / Ground**

Notes:
   * Applies to uncached SCSI/A adapters
   ** Applies to SCSI w/ cache adapters

Pin 59 and 60 are used to access the Serial Console on the uncached adapters.


Internal/External 68-pin Connector

68-pin Mini Centronics

This is the 68-pin Mini Centronics connector used on most fast/wide IBM SCSI adapters to connect internal and external devices (the two variants use similar connectors but the internal one lacks the metal shielding).

PinSignalPinSignal
1Ground35-Data 12
2Ground36-Data 13
3Ground37-Data 14
4Ground38-Data 15
5Ground39-Data Parity 1
6Ground40-Data 0
7Ground41-Data 1
8Ground42-Data 2
9Ground43-Data 3
10Ground44-Data 4
11Ground45-Data 5
12Ground46-Data 6
13Ground47-Data 7
14Ground48-Data Parity 0
15Ground49Ground
16Ground50Ground
17+Terminal power51+Terminal power
18+Terminal power52+Terminal power
19Reserved53Reserved
20Ground54Ground
21Ground55-Attention
22Ground56Ground
23Ground57-Busy
24Ground58-Acknowledge
25Ground59-Reset
26Ground60-Message
27Ground61-Select
28Ground62-Control/Data
29Ground63-Request
30Ground64-Input/Output
31Ground65-Data 8
32Ground66-Data 9
33Ground67-Data 10
34Ground68-Data 11


External 50-pin Connector

50-pin Mini D-Sub

This is the "industry standard" HPDB50 external SCSI connector (narrow; 8-bit). It's used by a very few IBM SCSI adapters:

PinSignalPinSignal
1Ground26-Data 0
2Ground27-Data 1
3Ground28-Data 2
4Ground29-Data 3
5Ground30-Data 4
6Ground31-Data 5
7Ground32-Data 6
8Ground33-Data 7
9Ground34-Data Parity
10Ground35Ground
11Ground36Ground
12Reserved37Reserved
13Not Connected38+Terminal power
14Reserved39Reserved
15Ground40Ground
16Ground41-Attention
17Ground42Ground
18Ground43-Busy
19Ground44-Acknowledge
20Ground45-Reset
21Ground46-Message
22Ground47-Select
23Ground48-Control/Data
24Ground49-Request
25Ground50-Input/Output


Sources

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