By default many Thompson routers have a SIP ALG enabled.  SIP ALG in most scenarios is damaging to voice over IP, often resulting in one way audio

Fortunately, a SIP ALG can be disabled on a Thompson Router using command line tools like telnet

Telnet is a free tool available on all windows computers

If it is not installed, you can activate telnet by entering Control Panel > Programs & Features > Turn Windows features on or off

Once enabled, open a command prompt (Start > Run, type CMD and then press enter) and do the following:

 

> ipconfig (Press “Enter”)

 

Find the line that tells you the IP address of the Default Gateway.  It will be similar to 192.168.0.1 or 192.168.0.254 or similar

 

> telnet 192.168.1.254 (ie telnet to the IP address found above)

 

The default username is admin and there is no default password ie leave it blank

 

> connection unbind application=SIP port=5060 (Then press “Enter”)

> saveall  (Press “Enter”)

> exit (Press “Enter”)

 

Then re-run our SIP ALG test to ensure that it is disabled

 

http://www.internetvoipphone.co.uk/sip-testing-tools/

 

SIP ALG in now disabled on your Thomson router.