IBM XT 5160 Technical Reference page 54

The speaker connector, J19, is a 4-pin, keyed, Berg strip. The
pins are numbered 1 through 4 from the front of the system. The
pin assignments are as follows:
Connector Pin Function
1
Data out
J19 2
Key
3
Ground
4 +5
Vdc
Speaker Connector (J19)
The keyboard connector, J22, is a 5-pin, 90-degree printed circuit
board (PCB) mounting, DIN connector. For pin numbering, see
the "Keyboard" section. The pin assignments are as follows:
Connector Pin Assignments
1
Keyboard Clock
J22
2
Keyboard Data
3
Reserved
4
Ground
5
+5
Vdc
Keyboard Connector (J22)
System Board 1-33