Setting up a Com Port in FreeBSD

 We have had several people wanting to add a modem, after they have already installed FreeBSD. One of the first things you need to do, is make sure that, the COM Port that the modem is on, is in the Kernel. If you don't know how to modify the Kernel, Click Here 

Kernel Example :

# PCCARD (PCMCIA) support
#controller   card0 
#device     pcic0  at card?
#device     pcic1  at card?

device     sio0  at isa? port "IO_COM1" flags 0x10 tty irq 4 vector siointr
device     sio1  at isa? port "IO_COM2" tty irq 3 vector siointr
device     sio2  at isa? disable port "IO_COM3" tty irq 4 vector siointr
device     sio3  at isa? disable port "IO_COM4" tty irq 3 vector siointr

device     lpt0  at isa? port? tty irq 7 vector lptintr

device     psm0  at isa? port "IO_KBD" conflicts tty irq 12 vector psmintr
 

The device siox (where the x is put in the port number, starting with Com1 as 0)
reflects what port your modem will be set on, for example, if you have a modem on Com4, then it should be 
 device     sio3  at isa? disable port "IO_COM4" tty irq 3 vector siointr
Make sure to have the IRQ match what the modem is currently set at. If you have the modem on COM3 and a mouse on COM1, then you will have a IRQ conflict. So, you need to change the IRQ to something like IRQ 5, instead of IRQ4, this will fix the IRQ problem, and make sure to also change your modem to IRQ5 if this is something you do.

Next thing that we need to change, is the ppp.conf in the /etc/ppp directory. If you have not yet did the setup for ppp Click Here. The below are setting that you can use to make sure you have the correct /dev device setup for the correct Com port that you are using.

Default settings:

-Example: Com1 = /dev/cuaa0
-Example: Com2 = /dev/cuaa1
-Example: Com3 = /dev/cuaa2
-Example: Com4 = /dev/cuaa3  

Written By: GhostRdr

ghostrdr@defcon1.org