Use of the Instant Fax ATA system requires you to purchase a proprietary ATA from ParagonVoIP. To place an order, contact your sales representative or email Your sales rep will work with you to select a new or existing fax line, and setup the initial support ticket to implement the system.

Setup and management of your Instant Fax ATA is completed via ParagonVoIP support. All changes are to be requested via your support portal or via email at


Although it is possible to send faxes through any SIP ATA that is registered to the PBX using T.38 or G711 pass-through, these methods do not always satisfy the heavy fax user.  This is a reflection of the fact that fax machines are especially vulnerable to latency and jitter.   As a result, network problems that may not impede a regular voice call often interrupt a fax transmission and result in a dropped call.

The Instant Fax ATA Store-and-Forward solution allows faxes to be buffered before being transmitted to an analog fax machine.    

  • For Inbound (DID) calls, faxes are received in the ParagonVoIP data center (where last mile latency and jitter issues are not a concern) by a Store-and-Forward fax server and then transmitted to the ATA using a file transfer protocol that is not susceptible to latency and jitter concerns.  Once they are received by the ATA, they are relayed to a local fax machine that is connected to the ATA with standard RJ-11 cabling.
  • For Outbound (Termination) calls, faxes from a local fax machine are intercepted and stored by the ATA and then transferred to a Store-and-Forward fax server in the ParagonVoIP data center using a file transfer protocol that is not susceptible to latency and jitter concerns.  From the fax server, they are relayed to the PSTN using high-bandwidth SIP connections.


Please refer images below for Fax Appliance:


As the Instant Fax ATA solution uses the HTTP protocol to overcome last mile latency and jitter problems, this system is separate from and operates independently of the WebCentrex platform.  In order to troubleshoot fax issues, please open a ticket by emailing including the approximate time, ANI and DNIS of the fax session with trouble.