(Followup to comp.os.linux.networking.)
I'm not able to use a multi-port card on a PC/Linux.
The card is named "PC COM 8 port", has eight RS232 serial ports,
is plugged on an ISA 8bits bus, and the documentation says it's
It seems the card is recognized by setserial and I can talk with
the Kortex Pro 144 modem on any port. But hardware flow control
(RTS/CTS) doesn't work at all. The modem is OK, since it accepts
hardware flow control when I put it on "normal" ports, COM1
(mouse port) or COM2. An US Robotics Sportster 14 400 doesn't
work at all (I cannot even send "AT") on the multi-port card but
is OK on the "normal" serial ports. The wiring seems fine since
DTR signal is always seen by both modems when the software runs
and tries to access the one of the card's serial ports.
I tried to drive the modems with minicom and uugetty and the
symptoms are the same (the Kortex works without flow control
only and the USR doesn't work).
I suspect that the signals from the card are too low: the Kortex
recognizes them partially and the USR not at all (except DTR).
Is it possible? The multi-port card is close from the video
card. May they interfer?
The Serial-HOWTO says that Arnet cards are supported on Linux.
It gives no detail about them, referring to the rc.serial
script. That script contains nothing about Arnet. Anyway, both
the rc.serial script and the card's documentation only talk
about I/O addresses and IRQ levels to find the port. They
mention nothing else which might cause problems. And I believe
the I/O addresses and IRQ settings are fine since DTR is
consistently detected on both modems: it means the ports are
found by Linux.
Linux kernel is 1.2.13. Apart from the kernel, which was rebuilt
from recent sources, the distribution is the Slackware from