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
  • 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 G.711 Fax over IP
  • Auto Fall back to G.711 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). Automatic fixing of bugs produced by Microsoft in different Windows versions
  • 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)
  • Easy integration with Windows Fax Service. Configuring Windows Fax Service to send/receive faxes via Fax Voip Virtual COM Ports (modems) in one click. Automatic installing of Windows Fax and Scan (Fax Server Role) during Fax Voip T.38 Modem installation. Creating shortcuts on the desktop and in the main menu. In Windows 11 and Windows 10, automatic bug fix in Windows Fax Service / Fax and Scan software (CallerID and TSID not stored after receiving a fax, 'Forward as E-mail' button is grayed out)
  • SendFaxMS.exe - Microsoft Fax command line utility. Sending a fax to one or more recipients. Support for multiple documents, cover pages, native e-mail delivery receipts. Tracking fax job. Configuring and running SendFaxMS.exe using the Fax Voip T.38 Modem Control Panel

Incoming Fax Routing Methods - Microsoft Fax (Fax Voip T.38 Modem Routing Extension)

  • Fax Voip T.38 Modem Routing Extension integrated into Windows Fax Service software
  • Route through e-mail Incoming Fax Routing Method (Microsoft Fax). E-mail Templates. Customizable attachment filename templates
  • Store in a folder Incoming Fax Routing Method (Microsoft Fax). Customizable filename templates
  • Print Incoming Fax Routing Method (Microsoft Fax)
  • Custom routing for incoming faxes (Microsoft Fax)

Outgoing Fax Routing Methods - Microsoft Fax

  • E-mail Delivery Receipts Outgoing Fax Routing Method (Microsoft Fax). E-mail Templates. Customizable attachment filename templates
  • Store in a folder Outgoing Fax Routing Method (Microsoft Fax). Customizable filename templates
  • Print Outgoing Fax Routing Method (Microsoft Fax)
  • Custom routing for outgoing faxes (Microsoft Fax)

 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, Codecs

 E-mail support: Mail to Fax, Fax to Mail, Delivery Receipts

  • Mail to Fax - Microsoft Fax. Multiple e-mail attachments, Cover Pages, Sender Information
  • Mail to Fax Rules - Microsoft Fax. Overriding depending on e-mail address: Dialing Rules, Delivery Receipts, E-mail Attachments, Cover Pages, Sender Information, E-mail Templates, Fax Priority and Schedule. Blocking unwanted e-mail addresses
  • Configuring Mail to Fax service to be started under regular user account instead of local system account
  • Fax to Mail (Route through e-mail Incoming Fax Routing Method) - based on using Microsoft Fax Service. E-mail Templates. Customizable attachment filename templates
  • Delivery Receipts via e-mail - Microsoft Fax (E-mail Delivery Receipts Outgoing Fax Routing Method). E-mail Templates. Customizable attachment filename template
  • Customizable E-mail Templates. Customizable date and time formats
  • SMTP support. CDO.Message, System.Net.Mail. Implicit SSL, Explicit SSL (STARTTLS). TLS version 1.2 support. UTF-8 encoding
  • Sending digitally signed e-mail messages. Clear signing. Opaque signing
  • POP3/IMAP support. SSL support. TLS version 1.2 support
  • Ignoring invalid e-mail server SSL certificate


  • Fax Voip T.38 Modem Control Panel. Ribbon user interface
  • Fax Voip T.38 Modem Manager
  • Possibility to run as Windows Service
  • Direct Converting to Fax. Supported formats: PDF, TIFF, SFF, QFX, BMP, JPEG, GIF, PNG, ICO, WMF (EMF)
  • Repair ‘printto’ verbs function. Supported formats: TXT, BMP, DIB, EMF, GIF, ICO, JFIF, JPE, JPEG, JPG, JXR, PNG, RLE, TIF, TIFF, WDP, WMF
  • Multi-Language support. Simple mechanism for translation into any language
  • Address Book (Windows Contacts) support
  • Checking for new versions of the program
  • Fax Voip T.38 Modem 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 11
  • Windows 10, Windows 10 64-bit
  • Windows Server 2022, Windows Server 2019, 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 **
  • Intel-compatible PC with 32-bit or 64-bit (x64) processor.
  • Microsoft.NET Framework 4.5 or later

* 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.

** Limited support. Some features may not work or work incorrectly. Windows 7 and Windows 8 are no longer supported by Microsoft.

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