IBM X.25 - Manual (Page 15)

Adapter Cable Options
The following adapter cables are available as options:
X.21 Cable (FRU Part Number 16F1865)
The X.21 cable is 3 meters (9.9 feet) long. It has a 37-pin
female connector at the adapter end and a 15-pin male
connector at the other end.
X.21 bis (V.24) Cable (FRU Part Number 16F1869)
The X.21 bis (V.24) cable length is 3 meters (9.9 feet) long. It
has a 37-pin female connector on one end and a 25-pin male
connector at the other end.
X.21 bis (V.35) Cable (FRU Part Number 16F1871).
The X.21 bis (V.35) cable length is 3 meters (9.9 feet) long. It
has a 37-pin female connector on one end and a 34-pin male
connector at the other end.
Note: These are the same cables used on the IBM X.25 Interface
Co-Processor/2 adapter on Micro Channel-based personal
computer systems and X.25 Interface Co-Processor used on
AT-compatible personal computer systems.
Product Description 1-3