I/O Ports and ConnectorsThe I/O ports and connectors on the back panel of your computer are the gateways through which your computer system communicates withexternal devices, such as a keyboard, mouse, printer, and monitor. Figure 3 identifies the I/O ports and connectors for your system.Figure 3. I/O Ports and ConnectorsKYBD/MOUSE Keyboard connector and mouse connector (stacked)LAN Wakeup On LAN card connectorLINE-IN Audio line-in jackLINE-OUT Audio line-out jackMEC_A MEC socket (channel A)MEC_B MEC socket (channel B)MIC Microphone jackPANEL Control panel connectorPARALLEL/SCSI Parallel port connector (sometimes referred to as LPT1) and SCSI connector (stacked)PCI1, PCI2, PCI3, PCI4 32-bit PCI expansion-card connectorsPCI5, PCI6 64-bit PCI expansion-card connectorsMT PWR1 Main power input connectorMT PWR2 Main power input connectorRAID Optional RAID PCI expansion card connector extensionSCSI_NARROW Secondary SCSI connectorSCSI_ULTRA2 Primary SCSI connectorSERIAL1/2 Serial port connectors (sometimes referred to asCOM1 and COM2; stacked)S2_PRI Primary Intel® Pentium® III Xeon™ microprocessor SEC cartridge connectorS2_SEC Secondary Pentium III Xeon processor SEC cartridge connectorTAPI TAPI input card connector (voice modem to audio system interface)USB USB connectorsWUOL Wake-Up on LAN connectorNOTE: For the full name of an abbreviation or acronym used in this table, see the Glossary.1 Parallel port connector 8 Diagnostic LEDs (See Messages and Codes.)2 Serial port 1 connector 9 Audio line-in jack3 Mouse connector 10 Audio line-out jack4 Keyboard connector 11 Microphone jack5 USB connectors 12 Serial port 2 connector6 Video connector (may be in first or second expansion slot) 13 External SCSI connector7 NIC connector