The module will typically can detect all of the installed cards.
Information from the detection is stored in the file:
Consider that a user has 3 NE2000 cards, one at 0x300 one at 0x240, and one at 0x220. You would add the following lines to the /etc/conf.modules file:
alias eth0 ne alias eth1 ne alias eth2 ne options ne io=0x220,0x240,0x300
What this does is tell the program modprobe to look for 3 NE based cards at the following addresses. It also states in which order they should be found and the device they should be assigned.
Most ISA modules can take multiple comma separated I/O values. For example:
alias eth0 3c501 alias eth1 3c501 options eth0 -o 3c501-0 io=0x280 irq=5 options eth1 -o 3c501-1 io=0x300 irq=7
The -o option allows for a unique name to be assigned to each module. The reason for this is that you can not have two copies of the same module loaded.
The irq= option is used to specify the hardware IRQ, and the io= to specify the different io ports.
By default, the Linux kernel only probes for one Ethernet device. You need to pass command line arguments to the kernel in order to force detection of furter boards.
To learn how furthere your ethernet card(s) work under Linux, you should refer to the Ethernet-HOWTO.