I recently had the need to integrate a phone system with ServiceNow such that callers could input certain data (like an employee ID) while on the phone using an automated system, and then have the phone system hit a particular URL which allows the fulfiller answering the call to be taken right to a new incident with the caller’s information pre-populated.
If you ever need to tie your phone system to your ServiceNow instance, there is a good chance that you want this link:
The CTI Processing business rule specifically is where you likely need to go if you need to customize any of what the pre-built computer telephony integration functionality.