Outbound Fax Made Easy with an Online Fax Service

3CX Phone System includes a fax service to receive faxes as PDF files, providing you use a supported VoIP Gateway or SIP trunk that supports the T38 fax protocol. However outbound fax functionality is not included.

We still get requests for outbound fax but implementing a fax server for the occasional fax really does not make sense. If you still send faxes from your PC, we recommend using an online fax service. There are several available which work remarkably well, are very reasonably priced and thus more cost effective than implementing a fax server.

Sending a fax from a fax printer driver or email client

An online fax service works in much the same way as an old style fax server does, allowing faxes to be sent from any Windows application via a fax printer driver or from any email client by sending the fax to  “<fax-number>@faxserviceurl.com”.


 Outbound Fax Made Easy with an Online Fax Service
Sending a fax via the fax printer driver (DuoFax)

Sendfax email

Sending a fax from an email client


Receiving faxes

Optionally these fax services will allow you to buy a fax DID and also receive faxes via email. This works identically to the 3CX fax service. Using the receive fax capability of these fax services makes sense if your SIP trunk provider does not provide T38 fax. In addition, the cost of a fax number at some fax services is much cheaper than an actual DID!

Available online fax services

We compared a number of online fax services and found DuoFax to work well and be competitively priced. There is no monthly fee, unlimited users, and the cost per page is between 3 cents and 5 cents per page. Importantly, it allows you to give all users in your domain the ability to send faxes, directly from their PC, without having to pay additional fees. However, there are many other options available. HelloFax – for example, charges a $10 monthly fee, includes 5 users and 300 pages per month, though inbound pages are counted as well. Whichever service you choose, it’s clearly time to say goodbye to your old fax server!

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  1. Brad

    Nick, I would respectfully disagree that an outbound fax server piece would not be beneficial to the 3CX offering. There are many business that require the faxing of certain documents and adoption/integration with 3rd party eSign providers is not universal. Even if it was built into 3CX Phone, would it be all that difficult to implement versus the added benefit of not having to turn to a third party when you have the SIP/POTS infrastructure already established?

    May 12, 2015 at 7:05 am
    • Hi Brad, You can of course implement a fax server if you still wish to use one. There are many fax servers still on the market, make sure you choose one with native t38 support. An easier solution is to get a t38 fax client – a good one is t38printer at t38printer.de. You can also use zoiper. There are no plans for outbound fax from 3CX.

      May 12, 2015 at 2:37 pm