HP dx7400 - Microtower PC Service & Reference Manual page 189

J30 PCI extender slot (male)
J31 - J35 PCI Express slots
J37 Primary SCSI connector
J38 Secondary SCSI connector
J39 Stacked parallel/SCSI connector
J40 AGP slot
J41 x16 PCI Express slot for graphics
J50 First parallel port
J51 Second parallel port
J52 Double-stacked parallel port, Top = Port B, Bottom = Port A
J53 Parallel port over single Serial Port
J54 Parallel port over Serial Port and Video Port
J55 Parallel port over dual VGA ports
J65 DVI connector
J66 Keyboard connector, PS/2 (Closest to power supply)
J67 Mouse connector, PS/2
J68 Stacked mouse (Top)/keyboard (Bottom) connector
J69 Video connector, VGA
J70 Primary single USB connector
J71 Secondary single USB port
J72 Microphone jack
J73 Line-in jack
J74 Line-out jack
J75 Headphone jack
J76 Volume control
J77 Double-stacked headphone (Bottom)/microphone (Top) connector
J78 Double-stacked line-in (Top)/line-out (Bottom) connector
J80 Stacked serial/audio connector
J81 Primary double-stack USB, Top = Port 2, Bottom = Port 1
J82 Secondary double-stack USB, Top = Port 4, Bottom = Port 3
J83 Triple-stacked audio jack (line in, line out/headphone, microphone)
J101 Security board connector - for security card
J9020-J9029 PCI slots on riser card
J9030-J9034 PCI express slots on riser card
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