If you have multiple devices registered to the Gateway, you can call and transfer calls between these devices or extensions using easy-to-remember short codes.
Start by configuring your SIP devices as described in the SIP Login/prefix article. Specifically, use the GV10000000000x1 format to set up extension numbers (x1, x2, x3) for each of your devices. NOTE: The user name is case sensitive! You must use capital GV at the beginning and lowercase x when specifying extensions.
Your device configured as GV10000000000x1 becomes extension 101, x2 becomes extension 102, and so on.
You can dial between the extensions using the short codes as well as transfer calls using your device's transfer function.
Three-digit schemes would use SIP IDs ending in x0 through x9 for 100 - 109, or you can set up four-digit extensions in a similar way (x10 becomes short code 1010).