I installed CentOS 6 on a Dell Optiplex 790 with a StarTech.com dual serial port card, and the serial ports aren't being recognized. According to dmesg, only the built-in serial port is being recognized: # dmesg | fgrep ttyS serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A 00:08: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A And lspci -v doesn't show that any drivers are loaded for it: # lspci -v [snip] 03:00.0 Serial controller: NetMos Technology PCIe 9922 Multi-I/O Controller (prog-if 02 [16550]) Subsystem: Device a000:1000 Flags: fast devsel, IRQ 16 I/O ports at 2010 [size=8] Memory at e1a30000 (32-bit, non-prefetchable) [size=4K] Memory at e1a20000 (32-bit, non-prefetchable) [size=4K] Capabilities: [50] MSI: Enable- Count=1/8 Maskable- 64bit+ Capabilities: [78] Power Management version 3 Capabilities: [80] Express Legacy Endpoint, MSI 00 Capabilities: [100] Virtual Channel <?> Capabilities: [800] Advanced Error Reporting 03:00.1 Serial controller: NetMos Technology PCIe 9922 Multi-I/O Controller (prog-if 02 [16550]) Subsystem: Device a000:1000 Flags: fast devsel, IRQ 17 I/O ports at 2000 [size=8] Memory at e1a10000 (32-bit, non-prefetchable) [size=4K] Memory at e1a00000 (32-bit, non-prefetchable) [size=4K] Capabilities: [50] MSI: Enable- Count=1/8 Maskable- 64bit+ Capabilities: [78] Power Management version 3 Capabilities: [80] Express Legacy Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting What do I need to do to get these serial ports recognized? On some other CentOS 6 systems with StarTech.com serial cards they were automatically recognized (different hardware and not PCIe based). Thanks, Alfred