State of knowledge

November 2020

This article explains how to check the ProCall Enterprise Remote Office feature against your PBX for compatibility.

Remote Office allows you to initiate calls outside the company via your business phone, presenting your company phone number to the person you are calling, regardless of which device you are currently using. (One Number Concept).

Some phone systems support the Remote Office functionality natively, for others a comparable behavior can be brought about by emulating the function. To do this, your business phone briefly dials the entered remote office number in speakerphone mode. As soon as the connection is established, the call is transferred to the target subscriber. Depending on the telephone system, this is realized via a blind transfer or a consultation call, which is transferred immediately.


To activate Remote Office, use the line menu in the My presence area of the ProCall Client or Mobile App to enter the phone number that you can currently be reached on, the so-called Remote Office phone number (e.g., your mobile phone). This first sets up call forwarding to the Remote Office number on your business phone.

When dialing out, e.g. via ProCall Mobile, the telephone system calls the entered remote office number via your extension, and – as soon as this connection is established – the target party is called.

In case of an incoming call, the call forwarding of the extension takes effect and the call is forwarded directly to the remote office number.


The installation must support the following TAPI functionalities to use Remote Office:

  • native Remote Office support via TAPI


  • emulates via TAPI functions

Necessary TAPI functions

  • Set/delete call forwarding and request call forwarding status on the telephone system
  • Initiation of dialing without user interaction (direct dialing via speakerphone, handset on-hook)
  • Arranging a call via
    • consultation in ringing state (lineSetupTransfer and lineCompleteTransfer (LINETRANSFERMODE_TRANSFER)), or
    • direct forwarding via blind transfer (lineBlindTransfer)
  • Two outgoing lines are required to use Remote Office.

If these actions are performed without further user interaction and with expected signaling, there is compatibility with the telephone system.