I installed a 2 port serial PCI card on a system running CentOS 4.3, but I can't get the additional serial ports to work. The card I used is from StarTech (http://www.startech.com/Product/ItemDetail.aspx? productid=PCI2S550&c=US). When it is detected by kudzu, it shows up as a "NetMos Technologies PCI 9835 Multi I/O Controller". I've included the output of "lspci" and "cat /proc/pci" below. The (very sparse) instructions for Linux support for this card state that you should look for the string "serial port x" in the contents of /proc/pci, and then use that information with the setserial command to configure the port as follows: # setserial /dev/ttyS2 port 0xc000 uart 16550 irq 11 baud_base 115200 The problem is that I can't find the equivalent of the "0xc000" and the IRQ on my system in the contents of /proc/pci. Here is what the built-in, working serial port looks like: # setserial -a /dev/ttyS0 /dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4 Baud_base: 115200, close_delay: 500, divisor: 0 closing_wait: 30000 Flags: spd_normal skip_test auto_irq Any ideas how to get these serial ports working? Thanks, Alfred # lspci 00:00.0 Host bridge: Intel Corporation 945G/GZ/P/PL Express Memory Controller Hub (rev 02) 00:02.0 VGA compatible controller: Intel Corporation 945G/GZ Express Integrated Graphics Controller (rev 02) 00:02.1 Display controller: Intel Corporation 945G/GZ Express Integrated Graphics Controller (rev 02) 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01) 00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01) 00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 01) 00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 (rev 01) 00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 (rev 01) 00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 (rev 01) 00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 (rev 01) 00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01) 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1) 00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01) 00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) Serial ATA Storage Controller IDE (rev 01) 00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01) 02:00.0 Ethernet controller: Intel Corporation 82573E Gigabit Ethernet Controller (Copper) (rev 03) 0a:0a.0 Serial controller: NetMos Technology PCI 9835 Multi-I/O Controller (rev 01) # cat /proc/pci PCI devices found: Bus 0, device 0, function 0: Class 0600: PCI device 8086:2770 (rev 2). Bus 0, device 2, function 0: Class 0300: PCI device 8086:2772 (rev 2). IRQ 5. Non-prefetchable 32 bit memory at 0xd0100000 [0xd017ffff]. I/O at 0x30c0 [0x30c7]. Prefetchable 32 bit memory at 0xc0000000 [0xcfffffff]. Non-prefetchable 32 bit memory at 0xd0180000 [0xd01bffff]. Bus 0, device 2, function 1: Class 0380: PCI device 8086:2776 (rev 2). Non-prefetchable 32 bit memory at 0xd0200000 [0xd027ffff]. Bus 0, device 27, function 0: Class 0403: PCI device 8086:27d8 (rev 1). IRQ 11. Non-prefetchable 64 bit memory at 0xd01c0000 [0xd01c3fff]. Bus 0, device 28, function 0: Class 0604: PCI device 8086:27d0 (rev 1). IRQ 10. Master Capable. No bursts. Min Gnt=4. Bus 0, device 28, function 1: Class 0604: PCI device 8086:27d2 (rev 1). IRQ 5. Bus 0, device 29, function 0: Class 0c03: PCI device 8086:27c8 (rev 1). IRQ 11. I/O at 0x3000 [0x301f]. Bus 0, device 29, function 1: Class 0c03: PCI device 8086:27c9 (rev 1). IRQ 9. I/O at 0x3020 [0x303f]. Bus 0, device 29, function 2: Class 0c03: PCI device 8086:27ca (rev 1). IRQ 11. I/O at 0x3040 [0x305f]. Bus 0, device 29, function 3: Class 0c03: PCI device 8086:27cb (rev 1). IRQ 5. I/O at 0x3060 [0x307f]. Bus 0, device 29, function 7: Class 0c03: PCI device 8086:27cc (rev 1). IRQ 11. Non-prefetchable 32 bit memory at 0xd03c4000 [0xd03c43ff]. Bus 0, device 30, function 0: Class 0604: PCI device 8086:244e (rev 225). Master Capable. No bursts. Min Gnt=4. Bus 0, device 31, function 0: Class 0601: PCI device 8086:27b8 (rev 1). Bus 0, device 31, function 2: Class 0101: PCI device 8086:27c0 (rev 1). IRQ 9. I/O at 0x30b0 [0x30bf]. Bus 0, device 31, function 3: Class 0c05: PCI device 8086:27da (rev 1). IRQ 9. I/O at 0x3080 [0x309f]. Bus 2, device 0, function 0: Class 0200: PCI device 8086:108c (rev 3). IRQ 5. Non-prefetchable 32 bit memory at 0xd0080000 [0xd009ffff]. Non-prefetchable 32 bit memory at 0xd0000000 [0xd007ffff]. I/O at 0x4000 [0x401f]. Bus 10, device 10, function 0: Class 0700: PCI device 9710:9835 (rev 1). IRQ 11. Master Capable. Latency=32. I/O at 0x5030 [0x5037]. I/O at 0x5028 [0x502f]. I/O at 0x5020 [0x5027]. I/O at 0x5018 [0x501f]. I/O at 0x5010 [0x5017]. I/O at 0x5000 [0x500f].