If connecting via VoiceXML API, your callback URL is a HTTP(s) url to your application. See an example below:
https://api.example.com/webhooks/voice/calls
Additionally, you may add an events URL.
If connecting via SIP trunk, the URL follows the format trunk:IP_OR_HOSTNAME where IP_OR_HOSTNAME is the IP or URI to your SIP server where we should route incoming calls to. See examples below:
trunk:1.2.3.4
trunk:sip.example.com
Reach out to voice@africastalking.com for SIP details associated with your phone number and the IP to whitelist on your firewall.

