Re: Trouble with serial ports

Ray Olszewski Sun, 03 Nov 2002 09:05:17 -0800

OK. Since you've only been testing ttyS01 (the first of the 4 ports), we really do not know if the others are working or not. Your cabling looks good (subject to one hesitation; see below) and your other test standards look good too. So I'm drawn to the difference between the first STB 4Com port and the others in your configuration.

At 08:25 AM 11/3/02 -0800, Alan Womack wrote:

I have a chance to get back to this issue, it appears actually that none of the STB 4Com ports are working "correctly" I can get some "data" from od -v /dev/ttyS01 but it is a file of ^@ the control character and the longer I leave it up the more it gets whether data is being sent or not. I have tested /dev/ttyS00 with a null modem cable and details follow. I want to work on just /dev/ttyS01 at this moment.

[...]

setserial /dev/ttyS01 baud_base 9600 irq 3 port 0x02A8 ^fourport ^skip_test

[...]

root@webby:root# ./serial.ports
/dev/ttyS01, Line 1, UART: 16550A, Port: 0x02a8, IRQ: 3
        Baud_base: 9600, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal

Since the setserial probe finds a UART type associated with ttyS01, that device is configured correctly for *some* serial port. But since it also is using the standard values for the second serial port ... does your mobo have 1 or 2 serial ports (an onboard modem port counts)? My first thought is that you have an irq/ioport conflict (newer kernels support irq sharing, but you can't share ioports). If you do, either move S01 to a different itq/ioport combination, or make sure the modem/serial port is diaabled in the mobo's BIOS.

If that is not the problem ... I don't have experience with the specific 4-port card you are using, but I do recall that some multiport cards (the old BocaBoard 8 comes to mind) did not provide all of the control signals (DTR/DSR. RTS/CTS, DCD), while onboard serial ports pretty reliably do. You might want to retest with a null-modem cable that loopbacks the control signals rather than one that passes them through (even appropriately crossed, as your cable does).

If none of that helps ... the only thing I am left with is wondering if the card itself works. You might want to repeat the tests using the port associated with ttyS02 as a check.

--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski -- Han Solo
Palo Alto, California, USA [EMAIL PROTECTED]
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Re: Trouble with serial ports

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