R2 to SIP Gateway

R2 MFC VoIP Gateway or R2 MFC to SIP Signaling Converter

  • up to 16 E1 interfaces
  • up to 480 VoIP channels
  • SS7, ISDN PRI, V5.2, R2 CAS, R2 MFC, R 1.5
  • voice codecs G.711, G.723.1, G.726, G.729a/b, GSM
  • registration and authentication – up to 5000 SIP-subscribers
  • fax over G.711, T.38 fax relay
  • Echo Cancellation
  • SNMP monitoring
  • SyncE (option)
  • Single/Dual-redundant 220 VAC or 48/60 VDC Input

The R2 MFC VoIP Gateway is designed for the reconstruction and integration of telecommunications TDM equipment with support for R2 signaling system (type CAS) in IP, IMS and NGN networks.

R2 VoIP Gateway, thanks to the implementation and support of R2 MFC signaling is an optional product of the Terratel SIP/E1 Gateway model.

Network Diagram R2 MFC VoIP gateway for integration TDM to IP network

Pic 1. SIP to R2 MFC Gateway Connection Block Diagram.

R2 MFC (Multi-Frequency Compelled) signaling is a Channel Associated Signaling (type CAS) protocol.

R2 VoIP Gateway from Terratel can smoothly combine subscriber access networks and TDM digital switch nodes with next generation IP networks by converting SIP and R2 MFC signaling.

An additional function of this product is the conversion of the R2 MFC signaling to SS7 or ISDN PRI.

Key Features

  • Supports R2 MFC signaling system
  • Supports integrated IP-PBX functions
  • Simultaneously supports SS7, ISDN PRI, V5.2 and R2 CAS signaling within a single device
  • Provides for combining several PBXs into a corporate network with internal dialing plan
  • Provides for integrating IP-TDM-IP, and TDM-TDM connections

R2 MFC Digital Signaling System

R2 signaling is a channel associated signaling (type CAS ) system developed in the 60 years of the last century and that is still in use today in Europe, Latin America, Australia, and Asia.

R2 MFC (R2 Multi-Frequency Compelled) signaling is a Channel Associated Signaling (type CAS) protocol used over E1 signaling networks.

R2 MFC is used to convey addressing information along a telephone trunk between two digital switches in order to establish a telephone connections.

Specifications of the R2 signaling system are defined in ITU-T Recommendations Q.400-Q.490

R2 MFC – Compelling signaling. In the E1, CAS protocols use timeslot 16 for line signaling (also called supervision) – on hook, off hook, etc.

Dual tones representing digits are used for called and calling numbers, sometimes called ANI and DID.

R2 VoIP Gateway supports the digital version of line signals and inter-register signals.

R2 signaling from switch to switch supports the following MFC call types:

  • Simple calls (Incoming and outgoing calls): This is the signaling used between a PBX and a Central Office for local calls and toll free call
  • Calls with Caller ID: This is used between central offices for tracking the call to report the number to the switch being called and to apply billing charges when necessary

Configuring and Settings R2 signaling protocol

When organizing two-way lines with R2 MFC signaling type you should set the parameters specific to CAS protocol to their required values in addition to setting parameters common to all signaling types:

  • Register exchange type
  • CAS bits inversion

For outbound connection you should set the following additional parameters to their required values:

  • Request ANI before answer
  • Request ANI in answer
  • Send 500Hz when ANI requested
  • Request retries count
  • MFS set for register exchange
Web Interface page for Configuring R2 MFC signaling system

Pic 2. Web Interface – Configuring and setting R2 MFC signaling protocols

For inbound connection you should set the additional parameter ANI Send Condition to its required value.

ANI – specific CID (Caller ID) version for Eastern Europe.

Integration of R2 Signalling System with SoftSwitch

We offer the gateway for upgrading telephone networks featuring multiple R2 MFC Signaling.

There are 2 options for using this gateway based on tasks to be solved.

Option 1 is used when it is required to replace the TDM Digital Switch with the SoftSwitch. If multiple subscriber nodes are connected to the TDM Digital Switch over the R2 MFC Signaling they can be switched to the SoftSwitch using the gateway as indicated on the following figure.

R2 MFC VoIP Media Gateway for integration PSTN and IP network

Pic 3. Network Diagram of the R2 MFC VoIP Gateway to the Softswitch and the Subscriber Digital Line Concentrator

In this case the R2 interface disconnects from the TDM Switch and connects to the gateway that is connected to the SoftSwitch via the SIP data communications network.

Integration of SIP subscribers through R2 signaling

Option 2 is used when it is required to connect VoIP subscribers from the local network to the PSTN number capacity. If the operator has the existing TDM Switch with free R2 interfaces the gateway on the TDM network side looks as the R2 subscriber node while on the IP network side it looks as the IP PBX where IP subscribers register (please see the figure).

R2 MFC to SIP VoIP Media Gateway for integration PSTN and IP networks

Pic 4. Incorporating R2 MFC VoIP gateway to TDM switch and IP network network Diagram

R2 MFC protocol conversion option

Since the gateway supports SS7, ISDN PRI, V5.2 and R2 MFC signaling it can be used as a protocol converter.
This is important when TDM networks are upgraded and it is required to adapt various telecommunications products to R2 MFC interface protocols.

Network diagram of using Signaling converter and protocols R2 MFC, SS7, DSS1, V5.2

Pic 5. Network diagram of using the device as a signal converter R2 MFC and SS7

R2 MFC VoIP gateway from the company Terratel is used in different options of conjugation of VoIP and TDM/PSTN networks for minimization of expenses and reduction of operational costs.