Calling Another Extension

최근 업데이트 : Feb 23, 2021 |
Prolog information
  1. Pick up the handset and dial the number.
  2. If the number is busy, you can arrange a ringback when free as follows:
    1. Dial any digit and hang up.
    2. When the extension you called is free again, your phone will ring (a burst of three rings). Pickup the handset.