The problem is an X.25 attachment 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 |
| 271 | Any | 07F3151 | Cable, X.25 attachment cable, X.21 (3 m) | Un-P1-Cx-Ty |
| 271 | Any | 53F3926 | Cable, X.25 attachment cable, X.21 (6 m) | Un-P1-Cx-Ty |