On Wed, 12 Aug 1998, Maarten van Leunen wrote:
>Do you have any idea how an Internal Modem occupies a serial port? Does
>the modem actually use the IRQ of ttyS4 or does the modem itself also
>have an IRQ, or are both IRQs the same or what exactly?
A serial port is on a card which plugs into an ISA slot. The internal
modem is on its own card which also plugs into an ISA slot. Both must use
up an IRQ and an I/O port. The I/O port is like a memory address range,
but is evaluated within what one might call an "I/O address space", and is
necessary to read from, to write to, and to check the status of the
device. The IRQ identifies a unique interrupt number which is used to
asynchronously notify the operating system that it needs to check the
device for some sort of status change, i.e. the arrival of new input data.
An internal modem has exactly the same requirements as a serial port. The
only difference is that its connection is completely within the box, which
gives it the illusion of being somehow different and/or special. In fact,
however, its only difference is in its physical appearance. It's no
different, really, from an external modem connected to a serial port.
>I checked, Serial Ports have the exact same match used by standard
>installation. So no IRQ conflicts between serial ports.
You'll have to take the internal modem card out and compare its jumpers
and DIP settings in order to discover which I/O port and IRQ it has been
configured to use. If it conflicts with something else on your system,
then you'll have to alter the jumper/DIP settings on the card to make it
more cooperative.
--
Dave Mielke | Phone: 1-613-726-0014
856 Grenon Avenue | Email: [EMAIL PROTECTED]
Ottawa, Ontario |
Canada K2B 6G3 |
