| I/O | 
| Option # | Manufacturing Part #
 | Description | Previous Part #
 | 
| 4121A
 [S] | 501-5966 | Sun Fire Link Assembly | n/a | 
|  | cPCI Fire Link Optical Module (Paroli)
 | n/a | 
|  |  | n/a | 
|  | Sun Fire Link I/O Assy w/o WCI ASIC
 | n/a | 
|  |  | n/a | 
|  |  | 501-5599
 [F] | 
|  | Sun Fire Link I/O Assy, without Optical Module
 | n/a | 
| X4170A
 [S] | 540-4946 | Sun Fire Link Switch | n/a | 
|  |  | n/a | 
|  |  | n/a | 
|  |  | n/a | 
|  |  | n/a | 
|  | Backplane + AC Harness + AC Module
 | n/a | 
| X4175A
 [S] | 540-5477 | Sun Fire Link Optical Module | n/a | 
|  | cPCI Fire Link Optical Module (Paroli)
 | n/a | 
| X4180A
 [S] | 537-1022 [F] | Sun Fire Link Optical Cable, 5m | n/a | 
| X4181A
 [S] | 537-1023 [F] | Sun Fire Link Optical Cable, 12m | n/a | 
| X4182A
 [S] | 537-1024 [F] | Sun Fire Link Optical Cable, 20m | n/a | 
| X4575A
 [S] | 501-6030 | hsPCI I/O Board with PCI Cassettes | 501-6302 | 
|  | hsPCI Board without PCI Cassettes
 | n/a | 
|  |  | n/a | 
|  |  | 501-5599
 [F] | 
| X4576A
 [S] | 501-6440 | hsPCI+ I/O Board with PCI Cassettes | n/a | 
|  |  | n/a | 
|  | hsPCI+ I/O Board without PCI Cassettes
 | n/a | 
|  |  | 501-5599
 [F] | 
| 501-7282 | hsPCI+ I/O Board with PCI Cassettes | n/a | 
|  |  | n/a | 
|  |  | 501-5599
 [F] | 
|  | hsPCI+ I/O Board without PCI Cassettes
 | n/a | 
| X4576A-Z
 [S] | 501-7483 | hsPCI+ Assembly, L | n/a | 
|  |  | n/a | 
|  |  | n/a | 
|  | hsPCI+ I/O Board without PCI Cassettes, L
 | n/a | 
| X4577A-Z
 [S] | 501-7895 | hsPCI-X Assembly, L | n/a | 
|  |  | n/a | 
|  |  | n/a | 
|  | hsPCI-X I/O Board without Cassettes, L
 | 501-7602 | 
| n/a | 501-7602 | hsPCI-X Assembly | n/a | 
|  | hsPCI-X I/O Board without Cassettes
 | n/a | 
|  |  | n/a | 
|  |  | n/a | 
| n/a | 501-7874
 [F] | hsPCI+ I/O Board without PCI Cassettes, L | n/a |