October 2023

This overview provides information about the features provided by estos ProCall Enterprise in operation on SIP end devices via estos uaCSTA Server and estos ECSTA for SIP Phones (TAPI) and in operation of estos SIP Softphones via direct SIP communication with a virtual telephone system (SIP).

ProCall Enterprise

V 8.3

V 7.0

PBX/Cloud PBXHFO Crown Centrex – Crown Call Manager 1.4
with device/telephoneSnom 320
TSPECSTA 6  for SIP Phones 

This overview delivers information about estos ProCall Enterprise supported features operating on SIP devices via estos uaCSTA Server and estos ECSTA for SIP Phones (TAPI). In addition, it provides information on estos ProCall Enterprise softphone operations via direct SIP communication to the virtual cloud PBX (SIP).


ProCall Enterprise client for Windows

ProCall Mobile app ***





Hang up

Answer call

Hold call

   ☑ *1

Call back

Reject call

Forward call (without answering)

Forward call (after answering)

Set up a consultation call


Connect a consultation call

Initiate second call (e.g. from Hold)

Accept second call

Reject second call

Forward second call (without answering)

Forward second call (after answering)

Create a conference call (3 participants)

Second call on SIP line

Caller receives busy

Caller receives busy

Incoming call on SIP Line while active mobile phone call:

  • Answer call

mobile phone call is terminated

mobile phone call on hold **

  • Reject

Caller receives busy

Incoming mobile phone call while active SIP line call:

  • Answer call

SIP line call on hold

SIP line call on hold

  • Reject

Add a further participant to a conference call

Remove a participant from a conference call

Pickup call
via UCServer (from 8.3)


  • TAPI – SIP

  • SIP – TAPI 

  • SIP – SIP 

Pickup call
via feature code


  • TAPI – SIP 

  • SIP – TAPI 

  • SIP – SIP


Dial ringing tone

Call forwarding

  • Provided by PBX via TAPI

  • via feature code

  • provided by UCServer *2

Call protection/Do not disturb

  • via presence

  • via line


Function available
Availability or function planned
Not relevant
Not applicable due to technical limitations
Function not tested, full tests are pending
*1Presentation of 'hold' state planned
*2Call forwarding by UCServer configurable for internal/external/all calls always or while busy
**Depending on the functions of the network provider
***Supported functions for SIP lines in ProCall Mobile apps for connection via estos UCConnect

Release Note

Since estos has no influence on the further development of the supported telephone systems by the manufacturer, we cannot guarantee that the manual described above is also valid for future releases and e.g. other end devices without restrictions.