SFP VoIP E1 Converter

SIP E1 Gateway in SFP form factor for integration PSTN and IP networks


  • 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
  • Web-interface
  • SNMP monitoring
  • Network Element Remote Monitoring System


SFP VoIP E1 Converter is a unique equipment that is used in various options for pairing VoIP and TDM/PSTN networks (for connecting the E1 interface to an IP network). The device is designed to solve problems when the consumer needs to connect only one E1 interface to the IP network.

SFP VoIP E1 can act as a VoIP PRI gateway, VoIP R2D gateway and VoIP R1.5 gateway.

For ease of installation, the module is made in the 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 SFP VoIP E1 module via Ethernet switch

Рic 1. Sample of connecting SFP VoIP E1 module via Ethernet switch.

The support of ISDN PRI (DSS1, QSIG, Q.931) and R2 MFC signaling protocols used on the PSTN network allows the equipment to be used for the reconstruction and upgrade of legacy PBX used on the network.

SFP VoIP E1 Converter connect diagram

Pic 2. SFP VoIP E1 Converter connect block diagram.

Distinctive features

The SFP VoIP E1 converter design uses unique technologies to support the E1 interface.

SFP VoIP E1 Converter is designed to integrate TDM and IP networks.

The SFP VoIP E1 Converter is installed in the sfp-slot of network equipment, which allows it to be used in any place where the network is available.

Connection to the PBX is through the E1 interface.

This device has a hardware echo cancellation function for all voice channels of the E1 stream.

Key Specifications

  • Up to 30 simultaneous calls per 1E1 port
  • Supports E1 physical interface connections (G.703)
  • PSTN protocols support: PRI (DSS1, QSIG, Q.931), R2 MFC
  • Asterisk interface support
  • VoIP protocols support: SIP
  • Fax and modem support: Fax over G.711, T.38
  • Industry standard RJ-45 port
  • SFP form factor

Configuration Signaling PSTN and SIP Trunk

Terratel SFP VoIP E1 Converter supports up to 30 PSTN trunk connections in one E1 interface (PRI, R2 MFC).

In the direction of the IP network, the SFP VoIP E1 converter supports SIP.

For a physical connection to the PBX, the E1 interface is used, and to the IP network is the sfp-slot network equipment.

A simplified list of steps required to integrate the PBX and IP network using the SIP protocol:

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

The device is configured in the Settings tab of the Web interface.

Web interface - Configuring SFP VoIP Converter on the Settings tab

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

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

Diagnostics and monitoring

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

Web Interface - Monitoring the status of PCM channels of SFP VoIP converter on the Diagnostics tab

Pic 4. Web interface – Monitoring the status of PCM channels on the Diagnostics tab.

The displayed parameters of the Diagnostics subsection allow you to monitor the status of the device and its operation statistics.

For network monitoring, the device provides an integrated SNMP agent (SNMP v1/v2c). The real-time SNMP agent transmits messages about the incidents to the SNMP manager. Also, the SNMP agent supports monitoring of device states upon request from the SNMP manager.

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

Connecting SFP VoIP E1 module via Ethernet media converter

If during the deployment of the SFP VoIP E1 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 must use a budget media converter.

Connecting SFP-E1 module via Gigabite Ethernet Media Gateway

Pic 5. Sample of connecting SFP VoIP E1 module via Ethernet media converter

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