SIP PRI Gateway (SFP-E1)

SIP PRI gateway in SFP form factor for integrating TDM and IP networks

Photo SIP PRI E1 gateway with ISDN PRI, DSS1, QSIG support



  • 1 E1 interface (G.703)
  • SIP and RTP (up 30 VoIP channels)
  • ISDN PRI (DSS1, QSIG, Q.931), R2 MFC
  • fax over G.711, T.38 fax relay
  • Hardware Echo Cancellation
  • Web-interface
  • SNMP monitoring
  • Network Element Remote Monitoring System


SIP PRI gateway is a unique equipment used in various interface options for VoIP and TDM/PSTN networks (for connecting an E1 stream to an IP network). The device is designed to solve problems when the consumer needs to connect only 1 E1 stream to the IP network.

SIP PRI gateway can function as VoIP PRI gateway.

For ease of installation, the module is designed in an SFP form factor and can be inserted into any switch or media gateway that has an SFP slot (see photo below) and does not take up additional space.

Connecting SIP PRI Gateway via Ethernet switch

Рic 1. Sample of connecting SIP PRI Gateway via Ethernet switch.

Supports PRI (DSS1, QSIG, Q.931) and R2 MFC signaling used in the PSTN network, allows the equipment to be used to restore and update the PBX used in the network.

SIP PRI Gateway Connection Block Diagram

Pic 2. Connection diagram of the SIP PRI Gateway.

Distinctive features

The SIP PRI E1 converter design uses unique technology to support the E1 interface.

The SIP PRI gateway was designed to integrate TDM and IP networks.

The SIP PRI Gateway Converter plugs into the SFP slot of the network device, so it can be used wherever there is a network.

Connection to the PBX is carried out through the E1 interface.

This device supports hardware echo cancellation for all E1 voice channels.

Key Technical Characteristics

  • Up to 30 simultaneous connections to port 1E1
  • Support for connecting the physical interface E1 (G.703)
  • PSTN protocol support: PRI (DSS1, QSIG, Q.931), R2 MFC
  • Asterisk interface support
  • VoIP protocol support: SIP
  • Fax and modem support: fax via G.711, T.38
  • Standard industrial RJ-45 port
  • SFP format

Configuring PSTN and SIP Trunk Signaling

Terratel’s SIP PRI Converter supports up to 30 PSTN trunk connections in a single E1 digital stream (PRI, R2 MFC).

Towards the IP network, the SIP PRI gateway supports the SIP protocol.

For physical connection to a PBX or PSTN, the E1 interface (RJ-45 connector) is used, as well as to the sfp slot of the IP network of the network equipment.

A simplified list of steps required to integrate a PBX and an IP network using SIP:

  • Configure the physical connection of the E1 interface
  • Select and configure the desired TDM network signaling
  • Configure SIP protocol
  • Reboot your device

The device is configured on the “Settings” tab of the web interface.

Web interface - SIP PRI Gateway settings on the Settings tab

Pic 3. Web interface – Device settings on the “Settings” tab.

The list of configurable parameters consists of three sections – NETWORK, E1 PORT and DSS1.

Diagnostics and monitoring

The Diagnostics subsection of the embedded web interface is used for real-time monitoring of the status of PCM channels (E1 interface), SIP channels and call statistics.

Web interface - Monitoring the status of SIP PRI gateway channels on the Diagnostics tab

Pic 4. Web interface – monitoring the status of PCM channels in the “Diagnostics” tab.

Using the parameters displayed in the “Diagnostics” subsection, you can monitor the device status and performance statistics.The machine is equipped with a built-in SNMP agent (SNMP v1/v2c) for network monitoring. The SNMP agent sends alert messages in real time to the supervising SNMP manager. The SNMP agent also supports monitoring device status as requested by the SNMP manager.

The meaning and description of the variables provided by the SNMP agent on the device are listed in the corresponding MIB file.

Connecting SIP PRI Gateway Module via Ethernet Media Converter

If, when implementing the SIP PRI module for connecting communication systems based on the SIP protocol and devices using the E1 interface, it is not possible to connect it to a local area network (LAN), you should use a budget media converter.

Сonnecting a SIP PRI Gateway via an Ethernet media converter

Pic 5. An example of connecting a SIP PRI Gateway via an Ethernet media converter.

These media converters are designed to convert a signal and then connect a 1000BASE-SX fiber optic cable to a 1000 Base-T twisted pair cable.