IBM XT 5160 Technical Reference page 37

Schottky (LS) loads per slot. The IBM I/O adapters typically use
only one load.
Timing requirements on slot J8 are much stricter than those on
slots J 1 through J7. Slot J8 also requires the card to provide a
signal designating when the card is selected.
The following figure shows the pin numbering for I/O channel
connectors Jl through J8.
Rear Panel
B1
B10
B20
B31
, ,
, ,
, ,
, ,
,
A1
A10
A20
A31
Component Side
I/O Channel Pin Numbering (J1-J8)
1-16 System Board