Adding providers - marneu/GS3 GitHub Wiki
Adding providers starts in the web interface with Routes.
You have to enter a SIP-Gateway first and need some basic information from your provider. This is the most important part to connect to your provider. Read the annotations below the input masks, as they will provide some technical help. If your not familiar with regular expressions a good starting point is http://www.andymatthews.net/read/2009/10/22/A-beginners-guide-to-regular-expressions (you may find more on the web with the search term "regular expressions for beginners").
Common
Give a meaningful Title to ease the recognition in the config. You may want to name it like your phone or the base trunk number.
Registrar Server
The server where your account will be authenticated and calls are routed to you. Your Provider may request to use a Proxy as well (especially if you have a dialup DSL line).
Username
This depends on your provider, some use one account for all of your phone numbers, some use a different user per phone number. Enter your password for the user.
Dial Argument
Read the comment below the input mask. If you simply want to call to the outside world, a SIP/{number}@{gateway} may be enough.
Group
Leave empty for now.
is behind NAT
Is always yes if you have a dialup line (DSL) to the world.
Codecs
Only use those which your provider supports.
See the specials below for your provider.
Configure Gateways groups
Next you will need to add a gateway within Gateway groups in the menu.
Add a new gateway group if not already in the list and title it with your providers Registrar/Server (see before)
Permit inbound calls to receive phone calls.
See the specials below for your provider.
Return to the SIP gateways and set the Group now to the Gateway group just added or reviewed.
Configure Inbound Routes
If you add something, your entries must begin with a ^ otherwise you will have unpredictable results.