-----Original Message-----
From: Dan Brown <
> OK, I finally got the NIC working on this Compaq. However, I still
>can't get a properly-functioning serial port. Here's what's happening:
>
> First, the machine has one built-in serial port, so I attached an
>external modem to that port. It's set in the BIOS as COM1:, io 0x3f8,
>irq 4, and Linux automatically recognizes all of those settings--dmesg
>shows ttyS0 at those addresses, and setserial recognizes the UART as a
>16550a. When I run minicom and set it to use /dev/ttyS0, the modem
>doesn't respond at all, and none of the lights flash when I type
>commands.
>
> Second, I have an internal ISA hardware modem, which can work in PnP
>mode, or have its addresses set using DIP switches and jumpers. I first
>tried to use it in PnP mode, giving it io 0x2f8, 0x3e8, 0x2e8, and (I
>think) 0x100, with irq 3, 4, and 5, all as specified in the file
>generated by pnpdump. In every case, I got a fatal error allocating 8
>bytes of io at the requested address, even though /proc/ioports showed
>all of those addresses to be free.
>
> Being thus foiled, I decided to use the DIP switches to set the modem.
>I've mostly tried it at COM2, irq 3, and COM3, irq 4 and 5. What
>typically happens here is that I can start minicom and type commands,
>and the modem will respond--after a delay of about 15-20 seconds. When
>I've seen this problem before, it's been because the irq was set
>incorrectly, but in this case, it's set correctly--at least, setserial
>agrees with what I've set using the switches.
>
> I know that serial port conflicts are often a trial-and-error issue,
>but I'm not even sure what else to try here. Any help would be
>appreciated.
>
>--
>Dan Brown, KE6MKS, [EMAIL PROTECTED]
I have had similar problems before and I see your error. In the BIOS the
Com port gets an i/o address (3e8, 2e8, 3f8, 2f8 and printers get 378). In
the case of each modem your problem is that your modem i/o address is set
to other than the Com port. That is why the delay. You said your Bios
had COM1 at io 0x3f8 and irq 4 so you need the serial (external) port
modem set to 3f8. I don't know how you implement this but perhaps you
have a manual. You could however change the setting in BIOS until you
find the one the external modem is using. This may be easier, but will
require more reboots.
If you choose to concentrate on the internal then try Com 2 Irq 3 like you
did before. This time look in BIOS first to see what address is given for
Com 2. With either modem you must match up all three pieces: Com, Irq, i/o
address. After that is done all that is left is to make sacrifices to the
modem gods and pray a lot then try minicom again.
This is why upgrading a modem can be the hardest part of PC repair.
Hope this helps,
Brian
