| Description | Part Number |
| 128MB DDR DRAM DIMM | 40X5937 |
| 256MB DDR DRAM DIMM | 40X5938 |
| 512MB DDR DRAM DIMM | 40X5939 |
| 64MB Flash Card | 40X1455 |
| ACM Paper pick motor drive | 40X5410 |
| ADF assembly, Duplex X544 | 40X5468 |
| ADF assembly, Simplex X543 | 40X5469 |
| ADF Cable | 40X5479 |
| ADF input tray | 40X5470 |
| ADF rear duplex cover, X544 | 40X5478 |
| ADF rear simplex cover, X543 | 40X5477 |
| AIO Back cable cover | 40X5489 |
| AIO Link | 40X5537 |
| Bin full flag | 40X5872 |
| Cable packet | 40X5423 |
| Controller card, 3-1, No fax, X543 | 40X5465 |
| Controller card, 4-1, with fax, X544 | 40X5466 |
| Cover, bezel | 40X5533 |
| Cover, Dust (Extender) | 40X5441 |
| Cover, front | 40X5538 |
| Cover, left | 40X5417 |
| Cover, Logo | 40X5491 |
| Cover, right | 40X5486 |
| Cover, toner | 40X5534 |
| Cover, top | 40X5482 |
| Drawer, 550-Sheet Duo 100-Sheet MPF complete C54x, X543, X544 | 40X5434 |
| Fax interface cable | 40X5485 |
| Fax PCBA | 40X4820 |
| Flatbed asm | 40X5467 |
| Flatbed Cushion, X543 | 40X5539 |
| Flatbed Cushion, X544 | 40X5535 |
| Front middle cover | 40X5490 |
| Fuser drive motor | 40X5415 |
| Fuser exit sensor | 40X5413 |
| Fuser Maintenance Kit plus ITU, 110V | 40X2254 |
| Fuser Maintenance Kit plus ITU, 220V | 40X2255 |
| Fuser, X543, X544, 110-120V | 40X5406 |
| Fuser, X543, X544, 220-240V | 40X5407 |
| High voltage power supply | 40X5405 |
| ITU paper path thermistor | 40X5429 |
| ITU, Image transfer unit | 40X5403 |
| Low voltage power supply (universal power supply) | 40X5409 |
| Main drive gear asm, with motors | 40X5412 |
| Operator panel cable | 40X5481 |
| Operator panel DBCS, 3-1 | 40X5475 |
| Operator panel DBCS, 4-1 | 40X5476 |
| Operator panel, 3-1 | 40X5473 |
| Operator panel, 4-1 | 40X5474 |
| Output bin tray | 40X5484 |
| Photo sensor (one per package) | 40X5426 |
| Pick tires | 40X5168 |
| Power cord; 2.5 m, 8 ft. Europe, Middle East | 40X3141 |
| Printhead | 40X5411 |
| Redrive | 40X5492 |
| Release lever | 40X5536 |
| Scanner left cover | 40X5488 |
| Scanner right cover | 40X5487 |
| Separator pad | 40X5472 |
| Separator roller | 40X5471 |
| Toner cartridge contacts (Pogo pin) | 40X5421 |
| Toner density sensors, left or right (one per) | 40X5414 |
| Toner meter cycle card | 40X5404 |
| Tray, 250-sheet, C54x, X543, X544 | 40X5419 |
| Tray, 550-Sheet Duo Drawer, 100-Sheet MPF, C54x, X543, X544 | 40X5435 |
| USB (for thumbdrive) cable | 40X5480 |
| USB cable, packaged (2 m) | 40X1368 |
