IBM XT 5160 Technical Reference page 20

Expansion Unit Block Diagram
The following is an expansion unit block diagram for the IBM
Portable Personal Computer and IBM Personal Computer XT
with the 64/256K system board.
EXPANSION UNIT
Power Supply
130 Watt
4
Level
Receiver Card
from
Extender Card
a
Expansion Board
Osc i
11
ator
a-Slot
Expanded
I/O Channel
7
6
5
4
3
2
Note: A "System to Adapter Compatibility Chart," to identify
the adapters supported by each system, and an "Option to
Adapter Compatibility Chart," to identify the options supported
by each adapter, can be found in the front matter of the Technical
Reference Options and Adapters manual, Volume 1.
xix