Table of Contents
Using PPP and TCP/IP over a null modem connection
This is a very quick crash explanation of setting up a peer to peer IP link over serial. I researched this in order to use RF UART modules. This is what works for me. This is almost entirely ripped from this site (http://www.tldp.org/HOWTO/PPP-HOWTO/direct.html), but I wanted a local copy for myself.
- Two machines running linux with UART devices as /dev/ttyUSB0, configured at 115.2kbps.
- pppd installed
- Of my two RF modules, one has an FTDI UART↔USB chip onboard. The other has UART pins broken out. Connect RTS/CTS.
- Test the connection between the two units with minicom
On Machine 1:
pppd -detach crtscts noauth lock 184.108.40.206:220.127.116.11 /dev/ttyUSB0 115200 &
On Machine 2:
pppd -detach crtscts noauth lock 18.104.22.168:22.214.171.124 /dev/ttyUSB0 115200 &
These commands are nearly identical. The only difference is that the IP addresses (local:remote) are mirrored.