Skip to content

Fax Boxes

A faxbox is a virtual fax machine that enables you to send or receive faxes through email. Having a faxbox means that anyone using a fax machine can send a fax to your faxbox number and you can receive it as an email. Also, you can send paperwork to a fax machine from your faxbox email address.

Alternatively, you can set up a faxbox at Smart PBX > Users > User Features > Faxbox, see Setting up your faxbox.

Adding a faxbox

  1. Go to Callflows > Fax Boxes.
  2. From the left-hand navigation, click Add.
  3. Enter a name and assign an owner for the faxbox.
  4. Enter the email address for notifications.
  5. Click Advanced, then Options to define settings such as fax header, caller-ID, timezones, and retry limits.
  6. Save your changes.

See also: How do I send a fax?

Frequently asked questions

Q: Does your service support T38. If so, how can we enable it in our account?

A: You can send and receive fax data using 711 without any issues here. Carrier to carrier 711 will work out fine in 99.9 percent of cases. However, T38 is useful where there are bad links between the uas and uac but it might add some interoperability issues.

Q: How do I send a fax through email?

A: Ensure that you have a faxbox service setup already on your account, see Adding a faxbox. You should have a unique domain for sending faxes. You or your portal administrator can check this in Callflow App > Fax Boxes > Select fax box > Advanced > SMTP


  1. Create a blank email with no subject. In the "To" field of the email, enter the fax number as digits only followed by the custom address set for your company.


  2. Attach a single PDF to the email containing the fax content.

  3. Check that you have added the attachment, otherwise the fax will not succeed.
  4. Ensure that there are no other attachments such as pictures (email signatures count as a picture).
  5. Send the email.