Connect the IP-PBX to a SIP trunk
Connecting the enterprise IP-PBX to an Internet Telephony Service Provider's SIP trunk can mean significant cost savings as well as increased efficiency. The Ingate SIP Trunking module offers an easy and smooth transition to a modern and future-proofed SIP trunk provided by a service provider to connect to the traditional PSTN network. Read more about SIP trunking.
Test SIP at Ingate
Now it is easy to try how SIP communication works. Ingate offers you the possibility to, free of charge, register on the
trysip.ingate.com domain, which enables you to make calls, receive calls
and chat using SIP. You can also try the automatic SIP answering
machine. Read more 
All you need to know about SIP trunking
Ingate has established the SIP Trunking Network at www.siptrunk.org, an educational resource on SIP trunking. This Web-based portal will aggregate information from throughout the SIP trunking community in an industry-wide effort to educate enterprises about SIP trunking, to help simplify deployments.