
What it gives you
- Your extension, anywhere there is data. Wi-Fi or mobile, same number, same caller ID.
- One call history that covers both lines, with the line each call used marked on the row.
- Call recording for FireTone calls, stored on the phone and nowhere else.
- Push-to-talk, if your PBX has conference rooms — see the intercom.
- The line you meant. Per call, per contact, or one standing choice.
Which phone
The differences are not cosmetic. iOS does not let an app hold a SIP connection
in the background, and it does not open its call log to anybody. Both facts
shape what the app can do there, and both are covered where they matter rather
than being listed once and forgotten.