Virtual COM Ports (modems)

  • Up to 100 Virtual COM Ports (modems) to connect to standard fax program directly or via TAPI
  • Digitally signed Virtual COM port driver that is fully compatible with 64-bit versions of Windows 10, Windows 8/8.1, Windows 7, Vista, Windows Server 2016, Windows Server 2012/2012R2 and Windows Server 2008/2008 R2
  • Fax Voip 14.4K TAPI Voice-Fax Modem driver for modems (TAPI compliant)
  • Support for 3rd party Virtual COM Ports drivers
  • Simplified procedure of installing Virtual COM Ports and modems
  • Fax Class 1, UTI-T V.27ter/V.29/V.17, T.30 Fax Group 3 up to 14.400 Bauds
  • Error Correction Mode (ECM)
  • T.38 Real-time Fax over IP, T.38 UDPTL Redundancy, Force T.38 mode
  • Real-time Audio G711 Fax over IP
  • Auto Fall back to G711 Fax mode if T.38 not available
  • Real-time Audio Fax over ISDN CAPI 2.0
  • Color Faxes over VOIP and ISDN
  • Fax-On-Demand
  • Voice Modem support (UTI-T V.253 Conexant/Rockwell, audio formats: 16-BIT LINEAR, PCM, ALAW, ULAW)
  • Voice Modem support via Unimodem Audio Device driver (TAPI)
  • Voice Answering Machine support
  • Voice Greeting before sending or receiving fax
  • Remote Access to Voice and Fax Mailbox (DTMF)
  • Listening to a telephone line through computer speakers
  • Dialing a Phone Number Extension (DTMF)
  • Caller ID Number, Caller ID Name (direct COM-port connection and via TAPI)
  • Called Number (DID). Passing Called Number (DID) via Caller ID string (workaround)
  • Route through e-mail Incoming Routing Method (Microsoft Fax)
  • Store in a folder Incoming Routing Method (Microsoft Fax)
  • Print Incoming Routing Method (Microsoft Fax)

 Fax Voip built-in VOIP/ISDN Fax/Audio Lines

  • T.30 Fax Group 3 up to 14.400 Bauds
  • Error Correction Mode (ECM)
  • T.38 Real-time Fax over IP, T.38 UDPTL Redundancy, Force T.38 mode
  • Real-time Audio G711 Fax over IP
  • Auto Fall back to G711 Fax mode if T.38 not available
  • CAPI Fax. B3 Protocol 4: T.30 for Group 3 fax and B3 Protocol 5: T.30 for Group 3 fax extended
  • Real-time Audio Fax over ISDN CAPI 2.0
  • Fax Station ID, Fax Header
  • Separate ECM/Bitrate settings for outgoing/incoming, T.38/audio and modem/built-in faxes
  • CAPI fax: possibility to select B3 Protocol, Maximum Bitrate, disable ECM and enable High Resolution. Separated settings for outgouing and incoming CAPI faxes
  • Receiving faxes directly into TIFF, PDF or SFF files
  • Unlimited number of incoming fax sessions
  • Fax Voip Virtual Printer
  • Direct Document to Fax Converting. Supported formats: PDF, TIFF, SFF, QFX, BMP, JPEG, GIF, PNG, ICO, WMF (EMF)
  • Sending audio messages
  • Fax Voip Send Audio Message Wizard
  • Sending a fax or audio message to multiple recipients. Loading a list of faxes (phone numbers) from txt file
  • Sendfax.exe command line utility
  • SendAudio.exe command line utility
  • Fax Voip Console. Ribbon user interface
  • Scheduled fax or audio message sending, Delivery Notification via e-mail
  • Retrying and restarting of failed faxes and audio messages, pause and resume fax or audio message jobs
  • Viewing current status of outgoing and incoming faxes and audio messages in the Fax Voip Console
  • Saving faxes in different graphic formats: TIFF, PDF, SFF, BMP, JPEG, GIF, PNG, PCX.
  • Possibility to split faxes into pages when saving. Possibility to save only selected pages.
  • Route through e-mail Incoming Routing Method
  • Store in a folder Incoming Routing Method
  • Print Incoming Routing Method
  • Fax-On-Demand

 SIP/H.323/ ISDN CAPI 2.0 support

  • SIP over UDP, SIP over TCP and SIP over TLS support
  • SIP Outbound Proxy
  • Multiple SIP Registrations, Authentication Name, Domain/Realm, SIP Contact URL, Expires Header, Forcible SIP Registration
  • Direct SIP Call Routing
  • Possibility to change SIP User Agent
  • H.323 support, Fast Start, H.245 Tunneling, Telephone numbers list
  • Registration with H.323 Gatekeeper, Search for GK, Time to Live
  • H.235 MD5 GK Authentication
  • Direct H.323 Call Routing
  • ISDN CAPI 2.0 support
  • Direct ISDN CAPI 2.0 Call Routing
  • Possibility to select ISDN Controller # and B-channel # for outgoing ISDN CAPI 2.0 calls
  • Tel URI Scheme support (with SIP only)
  • VOIP audio formats: G.711-uLaw-64k, G.711-ALaw-64k, G.723.1, G.726-32k, GSM-06.10, iLBC, SpeexNB, SpeexWB
  • CAPI 2.0 audio formats: CCITT G.711 A-law, CCITT G.711 u-law
  • Dummy G.729 codec for compatibility with T.38 only
  • STUN server support
  • Outgoing and Incoming VOIP Call Routing
  • Overriding parameters via Call Routing: Username (Caller ID Number), Display Name (Caller ID Name), MaxBitrate, ECM, T38 UDPTL Redundancy, Fax Station ID, Fax Headline, Codecs

 Mail to Fax (Mail to Audio) and Fax to Mail

  • Fully-functional Mail to Fax and Fax to Mail system based on Microsoft Fax Service
  • Fully-functional Mail to Fax (Mail to Audio)and Fax to Mail system based on built-in VOIP/ISDN Fax/Audio Lines
  • Customizable Email Templates
  • Delivery Receipts via e-mail
  • SMTP support. CDO.Message, System.Net.Mail. Implicit SSL, Explicit SSL (STARTTLS).UTF-8 encoding
  • Sending digitally signed e-mail messages. Clear signing. Opaque signing
  • POP3/IMAP support. SSL support
  • Ignoring invalid e-mail server SSL certificate


  • Fax Voip Control Panel
  • Possibility to run as Windows Service
  • Multi-Language support. Simple mechanism for translation into any language
  • Address Book (Windows Contacts) support
  • Creating simple and complex (to large number of recipients) Microsoft Fax Service fax jobs using Fax Voip Virtual Printer
  • Checking for new versions of the program
  • Fax Voip Backup or Restore Wizard
  • Selective saving the configuration and user data when you reinstall the program
  • Unicode support
  • Full compatibility with operating system Visual Styles

System Requirement

Platforms supported* 

  • Windows 10, Windows 10 64-bit, Windows Server 2016
  • Windows 8.1, Windows 8.1 64-bit, Windows Server 2012 R2
  • Windows 8, Windows 8 64-bit, Windows Server 2012
  • Windows 7, Windows 7 64-bit, Windows Server 2008 R2
  • Windows Vista, Windows Vista 64-bit, Windows Server 2008, Windows Server 2008 64-bit
  • Windows Server 2003, Windows Server 2003 x64 Edition, Windows XP x64 Edition
  • Windows XP
  • Intel-compatible PC with 32-bit or 64-bit (x64) processor.
  • Microsoft.NET Framework 4.5 or later (Windows 10/8.1/8/7/Vista/2016/2012/2008)
  • Microsoft.NET Framework 2.0 Service Pack 1 or later (Windows XP/2003)

* FaxVoip Software does not guarantee the correct operation of the program when you install software on Virtual Machine of any type. In the case of specific problems in such installations, technical support is not provided.

Additional system requirements 

 Virtual COM Ports Software compatibility 

 Fax & Voice Software compatibility 

 Fax Software compatibility 

 Recommended VOIP service providers 

 SIP PBX Software compatibility 

 H.323 Software compatibility 

 Network requirements 

  • Network connection from the local computer to the SIP or H.323 server

** When using Microsoft Fax and Windows Fax and Scan, we currently recommend you to use our new solution, Fax Voip Windows Fax Service Provider (Fax Voip FSP), which was released in 2017. Fax Voip FSP replaces the standard Microsoft Modem Device Provider by the Fax Voip T.38/G.711FAX Device Provider. This allows you to use the Windows Fax Service most efficiently. In particular, the ECM (Error Correction Mode) is supported. The busy signal is also detected correct way. Fax Voip FSP implements Fax Voip FSP Routing Extension that is integrated into the Windows Fax Service. Fax Voip FSP stores the Called Number (DID) in the Routing Information field, which is available in particular in the Windows Fax and Scan software, in the incoming fax properties (no workarounds are used). Also, the Mail to Fax function is significantly improved. Using Fax Service Provider (FSP) instead of Virtual COM Ports and modems significantly improves reliability of your fax system.