Wireless HOWTO for Linux Systems

11. Appendix B - Siemens DECT Radio Modem

Web Site: http://www.siemens.com

What's that? These 2 components are not real PC cards but are more like modems that you use as external device.

Host1-serial - RadioModem1 - - - - - RadioModem2 - serial-Host2 

How can I connect it?

If you see them in an abstract vision you can model them like this:

Host1-serial - - NULL MODEM CABLE - - serial-Host2 

So you'd have a connection between 2 far serials with 2 possible configurations:

1. Linux with Windows, Linux has a daemon that answer to a ppp call while Windows has a Dial up connection under Remote Access.
2. Linux with Linux, where you can run (on all 2 hosts) a ppp connection, with IP addresses inverted.

For 1 you can use this simple script in Linux:

"/usr/sbin/pppd -detach lock idle 300 crtscts connect "/usr/sbin/chat -v TIMEOUT 5 AT OK AT OK AT OK AT OK" IPLINUX:IPWINDOWS /dev/ttySx 115200 disconnect "/usr/sbin/chat -v AT OK" ms-dns IPDNS"

where:

• /dev/ttySx is your serial port,
• IPDNS is the IP address of your dns server,
• IPLINUX is the Linux IP address as IPWINDOWS is the Windows IP address.

The above script is need for letting Windows believe there is a modem on the serial end!

In Windows you need to create a Dial Up connection with crtscts enabled, speed at 115200 and with a stupid number to call (need by Remote Access but absolutely not used).

With 2 Linux boxes you only have to run a very simple script like this at each Linux side:

"/usr/sbin/pppd passive local crtscts IPLINUX1:IPLINUX2 /dev/ttySx 115200 noauth persist"

where you'll invert IPLINUX1 with IPLINUX2 at the other edge.

Note that you can do authentication even Linux-Windows than in Linux-Linux if you want.