The problem is in the 4-port multiprotocol, X.21 cable. Use the following table to determine the part number for the field replaceable unit (FRU):
| CCIN or FFC | Type and model | Part number | Description | Location code |
| 260 | Any | 71F0164 | 4-port multiprotocol, X.21 cable | Un-P1-Cx-Ty |