Bitrix24 Call Tracking allows using SIP PBX numbers (SIP connector required). SIP connector is a special module that helps make outgoing calls and forward calls using your PBX.
SIP uses special headers containing the information about the destination number. These headers are saved to the log file. You can view call logs in the Call details section.
Bitrix24 automatically adds the detected number to the Sales Intelligence > Call tracking section.
More information in our Helpdesk article.