The following router models all feature "SIP ALG", and you will need to disable this for a sound and robust VoIP service from any VoIP provider: Technicolor TG582n PRO, Technicolor TG582n SB, Technicolor TG589, Thomson TG585 v7 and TG585 v8.
If you have a newer version of these routers, such as a TTG588v V2 or TG589Vac, you can view our FAQ on those routers here:
How do I disable SIP ALG in my Technicolor TG588v V2/TG589Vac?
To disable SIP ALG on these routers you will need to do the following on a Windows computer:
1) Press the Windows Start button and in the search box type in cmd and hit Enter
2) Type in telnet 192.168.1.254 and hit Enter. If this doesn't work, then you don't have Telnet installed and will need to go to Start → Control Panel → Programs → Programs and Features → Turn Windows Features on or off → Ensure TELNET CLIENT is checked and click OK.
For a Mac, you won't need to turn on any features like in Windows, simply open the Terminal Application and type telnet 192.168.1.254 and hitting enter:
3) When prompted, the default username is Administrator (case sensitive) and the default password is either blank or the serial number of the router (case sensitive):
Note: When you enter the information, no confirmation message will appear to let you know that SIP ALG has been turned off. Instead, if the command is typed correctly, a new line will appear beneath the command as seen below:
4) Type in "connection unbind application=SIP(TCP) port=5060" (without the quotation marks) and press Enter. If you get a 'unknown command' message returned once you press enter, then type in: "connection unbind application=SIP port=5060" (without the quotation marks)
5) Type in "saveall" and press Enter to apply and make this setting permanent.
6) Type in "exit" and press Enter to exit.