problem running both a slip CDMA modem and an ethernet card

I am running a system that uses a CDMA modem in slip mode on /dev/ser2, and an ethernet controller. I am setting the IP of the ethernet controller to, and the slip interface has its own IP associated with the CDMA modem ( I am also setting the default route to an IP within my company (not sure why, but it was there when I took over and the CDMA doesnt work without it ).

I am able to ping the modem IP and the LAN IP with no problem. The problem we are running to is we cannot telnet into QNX using the modem IP and ethernet IP at the same. Here are the commands we are using to initialize the network stuff:

#initialize ethernet
Net &
sleep 5
Net.ether82557 -v -I0 -l1 &
sleep 5

/usr/ucb/Socket -s1 &
/usr/ucb/ifconfig en1 up

#initialize modem
/usr/ucb/ifconfig lo0 localhost up
/usr/ucb/slattach /dev/ser2 115200
/usr/ucb/ifconfig sl0
/usr/ucb/route add default

I have a laptop hooked up to the ethernet controller via a crossover cable. If the CDMA modem gets reception then I can telnet over the ethernet. It takes a long time though, which makes it seem like the packets are getting bounced to the company IP through the CDMA modem. If the CDMA modem isnt in range, I cant get in at all through the ethernet IP.

Also, if I remove the route add default command then the ethernet works fine, but I cant telnet into it using the CDMA IP.

I think the problem is in the way the packets are getting routed. Does anyone have any ideas on how to fix this?