Networking-SLIP

[Bryan W. Maxwell]

Ive used slattach and ifconfig, to configure my SLIP connection. However 
when I use tcpdump, I dont see any packets being sent. What could be the 
cuase of this? If I try to cat > /dev/cuaa0 it says the device is busy. Yet 
i plug the serial cable into an oscilloscope and dont see any packets 
coming down the line. All the levels for the serial cable seem to be at 
minus 10. Ive tied pins 1 4 and 6 together to create a dumb 3 wire cable. 
Im connecting to a pic micro server which should be looking for its IP via 
slip connection to the computer. Any hardware/software tests or any help 
would be greatly appreciated.
Thanks in advance,
Bryan