On Fri, 2011-11-11 at 12:42 -0600, williambuell wrote: > I am a 62 year old beginner in Ubuntu. Thanks for any help, guidance, suggestions on this problem! > > I have used commands like the following to be certain that I have an active com port: > dmesg | grep ttyS > This won't necessarily tell you anything useful for several reasons. The prime one is that the default kernel parameters always create /dev/ttyS[0-3] regardless of whether your computer has any serial ports or not. The secondary reason is that, some time back you were right and reading through /var/log/messages showed serial ports (referred to as UARTS and normally with a hardware type of 16550) but more recent kernels don't do this - probably since UDEV device management became the norm. Neither of my systems (a laptop with serial ports, the other with 6 serial ports installed) give any grep hits for ttyS, UART or 16550 regardless of whether I use dmesg to feed grep or simply run grep ttyS /var/log/messages* The best way I know to find real serial ports is to use setserial with the -a option, which tells it to report on the state of the port without doing anything else. Here are a couple of examples: The first is on the machine with serial ports installed: # setserial -a /dev/ttyS0 /dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4 Baud_base: 115200, close_delay: 50, divisor: 0 closing_wait: 3000 Flags: spd_normal skip_test The second is on the laptop, which has no serial ports: # setserial -a /dev/ttyS0 /dev/ttyS0, Line 0, UART: unknown, Port: 0x03f8, IRQ: 4 Baud_base: 115200, close_delay: 50, divisor: 0 closing_wait: 3000 Flags: spd_normal skip_test The clue is the on the first line of setserial output: if it says "UART: unknown" then you're looking at one of the kernel's imaginary serial ports while if it says "UART: 16550A" or similar, you've found one which is mapped onto actual physical hardware and which, hopefully, has an accessible D-9 connector attached to it. I'm able to use any of my serial ports (/dev/ttyS[0-5]) from a Wine application without needing any symlinks: the application can find them directly, but the same application has never been able to find a known good USB serial adapter (supplied by pfranc some time back and used successfully with the Linux programs kermit and minicom) but, of course, ymmv. Martin
