How to disable SIP ALG on Thompson Technicolor Routers
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.