Make 3CX act like traditional PSTN Lines Center

Oct 03, 2023

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	Make 3CX act like traditional PSTN Lines

Solution Scenario:
Incoming call rings line 1, if no answer go to DR or VM, if busy go to line 2, if no answer go to DR or VM, if busy go to line3, etc...

General call routing:
SIP Trunk 1 or PSTN 1 --> 3CX --> DID 1 --> Extension 100
SIP Trunk 2 or PSTN 2 --> 3CX --> DID 2 --> Extension 200
SIP Trunk 3 or PSTN 3 --> 3CX --> DID 3 --> Extension 300
SIP Trunk 4 or PSTN 4 --> 3CX --> DID 4 --> Extension 400

DID 1-4 setup:
Route calls for this DID/DDI Number 1 to - Connect to Extension - 100
Route calls for this DID/DDI Number 2 to - Connect to Extension - 200
Route calls for this DID/DDI Number 3 to - Connect to Extension - 300
Route calls for this DID/DDI Number 4 to - Connect to Extension - 400

Extension setup:

100 - Destination Unreachable / Forwarding - No Answer - Digital Receptionist or Voicemail

100 - Destination Unreachable / Forwarding - Phone Busy - Use PBX Status - Forward to Extension - 200

100 - Destination Unreachable / Forwarding - Unregistered - Digital Receptionist or Voicemail

200 - Destination Unreachable / Forwarding - No Answer - Digital Receptionist or Voicemail

200 - Destination Unreachable / Forwarding - Phone Busy - Use PBX Status - Forward to Extension - 300

200 - Destination Unreachable / Forwarding - Unregistered - Digital Receptionist or Voicemail

300 - Destination Unreachable / Forwarding - No Answer - Digital Receptionist or Voicemail

300 - Destination Unreachable / Forwarding - Phone Busy - Use PBX Status - Forward to Extension - 400

300 - Destination Unreachable / Forwarding - Unregistered - Digital Receptionist or Voicemail

400 - Destination Unreachable / Forwarding - No Answer - Digital Receptionist or Voicemail

400 - Destination Unreachable / Forwarding - Phone Busy - Use PBX Status - Digital Receptionist or Voicemail

400 - Destination Unreachable / Forwarding - Unregistered - Digital Receptionist or Voicemail

IP phone setup:
Each phone will be configure with 4 extensions. All phones will share extensions 100, 200, 300, and 400, each representing a different line, for example,

Extension 100 = Line 1
Extension 200 = Line 2
Extension 300 = Line 3
Extension 400 = Line 4

When IP phones share extensions they will ring at the same time. The first to pickup with get the call (just like PSTN lines). The destination of the call is determined by the Extension setup, see above and customize as needed.

Keep in mind that all IP phones work a little different. We tested this configuration with a SNOM 370, Linksys 941 and Grandstream 2020. The Linksys required that I enabled call waiting on the phone to see when other lines where ringing. The Grandstream and SNOM seems to work without configuration changes.

Article Details

Article ID:

698

Created On:

Dec 18, 2009 01:54 PM