How to Send and Receive Fax (VoIP Fax Solution)

Yeastar S-Series PBX supports to send and receive faxes. In this guide, we introduce how to send and receive faxes by connecting a fax machine to S-Series PBX (the deployment of S-Series's VoIP fax solution).

  • To send faxes -to send faxes from S-Series VoIP PBX, you need to connect a fax machine to the PBX’s FXS port.
  • To receive faxes - to receive faxes over VoIP through a dedicated trunk or via fax detection. You can also send faxes to email, please refer to How to Send Fax to Email.

In This Guide

Sending Faxes from S-Series PBX

Step 1. Connect a fax machine to the PBX’s FXS port.
The fax machine will work as an FXS extension on the PBX. Here we connect the fax machine to the Span1_Port1.

Step 2. Configure an FXS extension.
Check “FXS” option for the extension, choose the FXS port where the fax machine connected to.
S-Series VoIP PBX Edit Extension

Step 3. Click “Save” and “Apply”.

Step 4. Go to “Settings > PBX > Call Control > Outbound Route”, create an outbound route.

Step 5. Set the Dial Pattern, select trunk and the FXS extension.

As the figure below shows, the dial pattern is “9.”, and strip 1 digit. You need to dial 9 before destination number to send fax over VoIP or traditional telephone line. For example, sending fax to number 05925503305, you need dial 905925503305 on the fax machine and then send your fax.

 Edit Outbound Route For Sending Fax from S-Series VoIP PBX

Note  Note: If you choose to send fax over SIP trunk (fax VoIP solution), you need to enable “T.38 Support” for the trunk in “Advanced” settings tab if the SIP trunk supports T.38

Step 6. Click “Save” and “Apply”.

Step 7. Now you can use the fax machine to send fax.

Receiving Faxes on S-Series PBX

Receiving Fax Over VoIP through a Dedicated Trunk

You can create one inbound route on S-Series PBX for fax receiving purpose only.
*In this way, the trunks selected for the inbound route could be used for fax receiving only and could not receive calls.

  1. Go to “Settings > PBX > Call Control > Inbound Route”, click “Add” to create a new inbound route.
  2. Select member trunks.
  3. Set the Destination as “Extension”, and choose the FXS extension.
  4. Click “Save” and “Apply”.

Receive Faxes Over VoIP through a Dedicated Trunk

Receiving Fax via Fax Detection

If you don’t want to assign a dedicated trunk for receiving fax, you can configure fax detection on the inbound route. When a fax reaches S-Series PBX, the PBX could detect it.
*In this way, the trunks could receive both calls and faxes.

  1. Go to “Settings > PBX > Call Control > Inbound Route”, edit one inbound route.
  2. Select the member trunks.
  3. Set the Destination as “IVR”.
  4. Check “Enable Fax Detection” option.
  5. Select Fax Destination as “Extension”, and choose the FXS extension.
  6. Click “Save” and “Apply”.

Edit Inbound Route and Enable Fax Detection



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  • 0



    How to set the IVR for receiving a fax?

    the IVR has no setting for the IVR?

    For example: IVR Prompt, hang up time and so on.


    Please advise to me

    Best Regards,


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