Here are some convenient test numbers that you can dial from SIP clients, Lumicall, or any other SIP or SIP-based WebRTC service.

Firefox users: there is currently a mismatch between Asterisk and Firefox that may cause your test calls to fail with the error Incompatible SDP. Lumicall and Chrome users have been able to call these tests successfully.

Jitsi, Lumicall
WebRTC browser
Time [click here] Announces time, hangs up
DTMF [click here] Press DTMF buttons and then hash, reads the numbers back to you and hangs up
Echo [click here] Echo test
Just ring [click here] The call is never answered, you should hear local ringback sounds

This service is powered by an Asterisk server

It should accept clients with or without encryption using either AVP or AVPF and a range of codecs are supported.