How to connect a listening modem


I am using sample_tcp.c file to start a listening TCP socket

I entered the AT commands;
–> trying to receive IP addres…
–>Local IP is abc.def.ghi.jkl
–>Gateway is asd.klm.ngj.kjh
–>Distant IP is NULL pointer

then I entered

Note: Listening IP is set to in Open AT application

–>TCP socket started in listening mode

then I typed ( into Start/Run) telnet
and I write in command line,
“open localip listeningPort”
–>could not open connection to the host

Note: This method works with any static IP addres.

then tried
“open Gateway listeningPort”
it does not work too,

Is something missing?


any IDEA?



Could it be that the IP-address you get assigned to your ME is private and behind a NAT-router (the ME and the PC is not on the same network)?

Can you PING the unit?



does not work
but modem works properly in client mode.



Try to use the Wavecom AT-command-controlled IP-application, that will give you an easy way to ping from the unit with AT-commands.

It sounds like the network assigns a private IP address to your ME and that the network gives your unit Internet access though a NAT-router.

Check if your IP asigned to your ME is in any private IP range:
Private IP range: - - -
Automatic private IP range: -

If the IP is not in the ranges above, check with your network operator what kind of access your SIM-subscription should have.