GL6110: Building a proxy for telnet <-> USB communication

hi all,

since there are SIM cards with fixed IP addresses i believe it should be possible to create a proxy program, running on the GL6110, which can be accessed through a telnet session and which forwards the received input to the target device attached via USB and returns the response from the target device to the telnet client.


  • client opens a telnet session and sends an ascii command
  • proxy forwards this to the target device which is connected via USB
  • proxy reads answer from target device and sends it back to telnet client

i had a look at the tcp_server sample application because i plan to start with it and then extend it with the USB sending/receiving part.
does all this make sense to you? is it doable at all? i’m completely new to embedded software development and m2m topics in general but i was asked to find a solution for this scenario.


Are you sure that the SIM IP address is also routable? i.e. Most ISPs provide you with an IP address in the non-routable range (10.x.x.x, 192.168.x.x). This IP address may be fixed, but will not be accessible from the internet in general.

I have done something similar to this on the old Fastrack Supreme using CSD - it proxied a dial-up connection to different serial ports.

Also depends on what’s on the other end of your USB link.

ciao, Dave

i was told that there are SIM cards with fixed IPs although i haven’t actually worked with one yet. i need to find out if they are routable… thanks for pointing this out!

yesterday i learned that with an IP VPN tunnel and a fixed IP SIM card the above scenario can be constructed.