SIP (group) trunking?


My ISP gave me group of number (example.:510-520) and one username and password for SIP trunking (u: 500 p: 1234 domain:
OK but I don’t know how can I setup this trunking in extension.conf or how can I mapping internal number (example 10-20) with external number (510-520)?

I have already work with SIP trunkung, but at that time I had have only one number.