UDP SOCKET access through AT# commands


If one is opening UDP socket using AT#LUDPSTART will the TCP/IP stack strip the incoming IP packets of all headers? Will it add the necessary headers when one tries to send IP data out?

I have a MultiTech modem connected to a embedded system and I am sending data over the serial connector.

Any help provided will be appreciated.


Hello brewd07,

Of course the stack removes and adds the UDP and IP header ( 80 + 80 byte in normal case) , and do lot of other things , that is way it’s called TCP/IP stack.

Best Regards,





I know that is the obvious answer but the thing is my packet was not reaching the destination and there was no way for me to sniff the IP packets as I am using a wireless modem. The header not being present was one of the possibility.

I just needed some confirmation.



Hello brewd07,

You can monitor the IP packets with AT+DLDBG=50 command on CUS4 level 25 TRACE messages, you can use the ethereal program to analyze the packets.

More info in the Tools Manual by the “TCP IP debug tool”.

Best Regards,




Where would I find information about AT+DLDBG command? I did a search on the internet and could not find anything.

Can I use Ethereal to monitor a wireless Modem?

Thanks for all your help.



Sorry, he command is AT+ADLDBG ( comes from ADL Debug probably), please look into the Tools Manual provided with the Open AT CD for more information.

Best Regards,