Your office call recorder
Your office phone system
POTS Line Telephony
PRI Line Telephony


Pricing | Range | Features and Benefits | Accessories | Typical Configurations | Product Specifications

Our latest OpenPRI v3 series of multi-port E1/T1/J1 line interface cards are offered in a half length PCI Express (PCI-e) bus form factor only. Positioned as a mid level hardware platform where connections to primary rate (digital) lines and legacy PBX phone equipment are desired, it supports both full and fractional lines and is ideally suited for medium to higher density voice traffic environments.

Typical telephony solutions targeted include:

  • Call Recording/Logging.
  • Traditional fixed line and IP based PBX phone systems.
  • Interactive Voice Response (IVR) answering services.
  • Automatic Call Distribution (ACD) systems.
  • Announcement systems.
  • Computer Telephony Integration (CTI) for contact centers.
  • Automated Dialers for contact centers.

Choose from our range of dual, quad and octal OpenPRI PCI express cards that best meet your telephony requirements:

Telephony Interface
Connects To
OpenPRI Dual
2 x E1/T1/J1 ports

Primary rate E1/T1/J1 ISDN lines. Supports up to 60 voice channels.

Optional PRI tap boxes provide the high impedance (Hi-Z) requirements to "passively" tap these primary rate lines for call logging/monitoring purposes.

Note: You need 2 x E1/T1/J1 ports to passively tap a single E1/T1/J1 line (up to 30 voice channels).

OpenPRI Quad
4 x E1/T1/J1 ports

Primary rate E1/T1/J1 ISDN lines. Supports up to 120 voice channels.

Optional PRI tap boxes provide the high impedance (Hi-Z) requirements to "passively" tap these primary rate lines for call logging/monitoring purposes.

Note: You need 4 x E1/T1/J1 ports to passively tap 2 x E1/T1/J1 lines (up to 60 voice channels).

OpenPRI Octal
8 x E1/T1/J1 ports

Primary rate E1/T1/J1 ISDN lines. Supports up to 240 voice channels.

Optional PRI tap boxes provide the high impedance (Hi-Z) requirements to "passively" tap these primary rate lines for call logging/monitoring purposes.

Note: You need 8 x E1/T1/J1 ports to passively tap 4 x E1/T1/J1 lines (up to 120 voice channels).


Half length PCI express form factor.
Install in a wide range of motherboards and chassis sizes.
Software configurable E1/T1/J1 ports.
The same telephony card can connect to any primary rate line in the world.
Supports full or fraction primary rate lines.
For instance in Australia, telecom service providers offer ISDN 10, ISDN 20 or ISDN 30 services.
Open Source Software Development Tools and Applications.
Speeds up development, provides total design and maintenance control and eliminates vendor lock-in, all at zero cost!
Applications include:
  • VTlogger, a web based call recording application.
  • OpenPBX for traditional fixed line PBX applications.
  • Accessories such as PRI Tap Box or PRI Switch Box.
    Offers a high impedance interface for passive tapping lines or redundacy against power or PC failure.
    Seamless integration with the OpenPCI series
    Ability to support both primary rate (digital) and analogue trunk lines with station ports on the same server. Ideal for PBX applications or channel bank replacements.


    Voicetronix has made available accessories that when combined with our telephony cards enhance and/or simplify telephony solutions that connect to digital lines. These include:

    PRI Tap Box - Passively taps E1/T1/J1 lines.

    E1/T1/J1 lines provide full duplex communication through 4 wires (ie. clock & data signals in separate directions - transmit & receive). In order to passively tap these digital lines for PC based call recording/logging applications, Voicetronix has specifically designed a PRI Tap Box that provides a high impedance connection that captures these signals with minimal reflections and feeds them into our OpenPRI dual and quad E1/T1/J1 port cards housed in PC servers. A seperate PRI Tap box has been designed and is available for the octal port card.

    You need two E1/T1/J1 ports to record the complete conversation (ie. one port captures the transmit side while the other port captures the receive). Once data (ie voice) is captured in each direction, it is synchronised and combined to provide the recorded call. The PRI Tap Box has four RJ45 sockets providing connection to the telco line, the customer telephone equipment and each of two E1/T1/J1 ports on our OpenPRI cards that run the VTlogger application.

    Note: The PRI Tap Box(s) can only be used with our OpenPRI dual, quad and octal E1/T1/J1 port telephony cards and together are designed to not interfere with the operation of your existing communication equipment.

    PRI Switch Box - Offers redundancy in case of PC server or power failure.

    The PRI Switch Box is ideal in situations where you are "breaking" the line between the telco and its connection to the customer equipment (usually a PBX) in order to provide, say, a PC based IVR answering service as an add on feature using our OpenPRI cards. In the event the PC server running the service suffers from a power or PC server failure the PRI Switch Box will automatically by-pass it by failing over the telco line to the customer PBX phone system. While the customer loses the add on feature, they doesn't lose the ability to make and receive calls. Alternatively the PRI Switch Box can be used to fail over to a redundant IVR server if so desired.

    The PRI Switch Box has four RJ45 sockets, one each for connecting to the telco line and customer equipment and two for connecting to our OpenPRI telephony cards. The PRI Switch Box and PC server communicate through a serial interface.

    Physical Connections
    Power Requirements
    Connection Info
    PRI Tap Box
    4 x RJ45
    Connects to OpenPRI dual E1/T1/J1 port cards running the VTlogger application via two of the RJ45 sockets. The other two RJ45 sockets connect to telco line and customer phone equipment, usually a PBX.
    PRI Switch Box
    4 x RJ45
    & 1 x RJ45 for (serial comms)
    12V DC or
    9V AC
    There is an RJ45 socket available to make connection to the telco E1/T1/J1 line, customer equipment and two E1/T1/J1 ports on the OpenPRI cards. Serial communication is made available by connecting the serial interface on the PRI Switch Box to the PC server's USB port via our modified serial RJ45 to USB cable.


    Telephony applications that our customers predominantly use the OpenPRI cards include call recording, IVR and CTI solutions. All you need to get started on building your own telephony solution is a PC server running Linux, an OpenPRI card, your choice of open source software and some sweat equity!

    If the DIY option is not for you then contact sales for a pre-configured or custom solution.

    Typical solutions include:

    • Providing call logging/monitoring functionality to existing primary rate trunked PBX phone systems. Take a PC server with the OpenPRI-Dual card running Linux (ie. Telephony server) and connect the PRI tap box to each E1/T1 port on the card, the telco line and the PBX. Install, configure and run our next generation telephony driver (libctpp) and VTlogger application software (VTlogger).
    • An IVR answering service with CTI capabilities supporting circuit switched (TDM) and IP based PBX phone systems. Take a PC server with an OpenPRI dual E1/T1/J1 port card running Linux (ie. Telephony server) and connect one of the E1/T1/J1 ports to the telco line and the other to the PBX phone system. Install our next generation telephony driver (libctpp) and commence developing your own custom IVR and CTI solution.


    Minimum System Requirements
    CPU/Speed    Intel Core i5 or AMD equivalent.
    Memory(RAM)    4GB or greater.
    MOBO/Backplane    Supporting 3.3V Power supply, PCI express X1 bus.
    Operating System    Linux.
    Technical Specifications
    Maximum boards per system    Application & System dependent (VTlogger has been tested to 960 channels.)
    Operating Temperature    0 to 50C.
    Form Factor    Half length PCIe (2U Form factor 120 x 55mm).
    CPU    On board ARM based 1.2GHz processor.
    Board Status    On board LEDs.
    Telephony Interfaces
    Number of Ports    Dual, Quad and Octal (up to 240 voice channels).
    Trunk Types    E1/T1/J1 (software configurable).
    Trunk Interface    Digital network interface.
    Physical Connection    2 or 4 x RJ45 connectors (pins 1, 2, 4 and 5).
    T1 Information
    Receive Clock Rate    1.544 MHz.
    Framing    SF(d4), ESF.
    Line Encoding    AMI, B8ZS.
    Signalling Protocol    ISDN, CAS.
    Alarms    LOS, LOF, Yellow & AIS.
    E1 Information
    Receive Clock Rate    2.048MHz.
    Framing    CRC-4, Non CRC-4.
    Line Encoding    AMI, HDB3.
    Signalling Protocol    ISDN, CAS.
    Alarms    LOS, Yellow.
    Primary Rate ISDN Signalling Protocols - Host based
          Euro-ISDN, National-ISDN2, Lucent 5E,
    AT&T 4ESS, DMS 100.
    Signal Processing
    Audio codecs    Mu-law, A-law, 16 bit signed Linear, Speex, GSM.
    DTMF Detector/Generator    0-9, *, #, A, B, C, D.
    Open Source Software Supported
    Software Development Kit (SDK)    Voicetronix GNU LGPL API library and utilities (libctpp).
    Application Software    VTlogger


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