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- Mar 4, 2020
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Hello,
I know how people cringe when someone mentions faxing and VOIP on this forum. There is also a million thread about it.
But there is one question I cannot seem to find the official answer to, either on this forum or with Google. (No, i'm not trying Bing!)
Q: Does 3CX officially supports ECM (Error Connection Mode) when receiving faxes through the built-in fax server?
All of our tests show the lack of ECM support

Actual capture of a fax received by 3cx fax server (ext.888)
We use Telnyx for inbound faxes and we are testing with a tool offered by one of our trunk provider t38fax.com to test ECM.
Their test results also confirm the lack of ECM support.
When receiving faxes with other systems, like direct to the ATA (bypassing 3CX), Grandstream UCM PBX or using Telnyx's API and Webhook system to receive faxes, ECM is working on the same DID.
Thank you for your clarification.
I know how people cringe when someone mentions faxing and VOIP on this forum. There is also a million thread about it.
But there is one question I cannot seem to find the official answer to, either on this forum or with Google. (No, i'm not trying Bing!)
Q: Does 3CX officially supports ECM (Error Connection Mode) when receiving faxes through the built-in fax server?
All of our tests show the lack of ECM support
Actual capture of a fax received by 3cx fax server (ext.888)
We use Telnyx for inbound faxes and we are testing with a tool offered by one of our trunk provider t38fax.com to test ECM.
Their test results also confirm the lack of ECM support.
When receiving faxes with other systems, like direct to the ATA (bypassing 3CX), Grandstream UCM PBX or using Telnyx's API and Webhook system to receive faxes, ECM is working on the same DID.
Thank you for your clarification.