R1.5 VoIP Gateway

Overview

SIP to R1.5 Gateway (R1.5 VoIP gateway) is used in different options of conjugation of VoIP and TDM/PSTN networks for minimization of expenses and reduction of operational costs. This gateway deliver reliable, high quality voice traffic between PSTN and VoIP networks.

CAS VoIP gateway due to the implementation and support of CAS type signaling is an optional product of the Terratel SIP/E1 Gateway model.

CAS or R1.5 signaling (for two dedicated signal channels) can be implemented by transmitting signals in the channels of PCM systems.

Support of all types of signallings being used on the PSTN network allows to use the equipment for reconstruction and upgrade of all types of automatic telephone exchange used on a network. Effective integration TDM to NGN and IMS networks.

Functionality

The device has the following important functional features:

• Supports R1.5 CAS signaling
• Up to 16 E1 and 480 SIP ports
• Supports integrated IP-PBX functions
• Simultaneously supports SS7, ISDN PRI, DSS1, QSIG, V5.2 and R2 MFC signaling within a single device
• Provides for combining several PBXs into a corporate network with internal dialing plan
• Provides for integrating IP-TDM-IP, TDM-TDM and IP-IP connections
• AC or DC backup power supply
• The possibility of reservation of communication using E1 bypass

Configuring and setting R1.5 CAS signaling

Inbound R1.5 Signaling

System R1.5 is an asymmetrical protocol that is widely used in East Europe over E1 trunks. It has provisions to interface with analog and digital switches.

Protocols R1.5 uses three different register signaling types:

• Decadic
• Multi-Frequency Pulse Shuttle (MFS)
• Multi-Frequency Continuous Packet (MFCP) (implemented specifically for the transmission of ANI information).

When organizing inbound lines over R1.5 protocol the corresponding signaling type should be selected: Inbound R1.5.

In addition to setting parameters common to all signaling types these signaling types should also have the parameters specific to R1.5 protocol set to their required values:

• Register exchange type
• CAS bits inversion.

You should also 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.

Outbound R1.5 Signaling

When organizing outbound lines over R1.5 protocol the corresponding signaling type should be selected: Outbound R1.5.

In addition to setting parameters common to all signaling types these signaling types should also have the parameters specific to R1.5 protocol set to their required values:

• Register exchange type
• CAS bits inversion

You should also set the additional parameter ANI Send Condition to its required value.

Migration of PBX subscribers with R1.5 signaling to IP network

Upgrade telephone networks using R1.5 signaling, the introduction of a specialized VoIP gateway is proposed.

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

Option 1 is used when it is required to replace digital TDM switch with the SoftSwitch. If a number of subscriber nodes are connected to the digital TDM switch via the R1.5 interface, they can be switched to the SoftSwitch soft switch using the VoIP gateway as shown in the figure.

If multiple subscriber nodes are connected to the TDM Switch over the R1.5 interface they can be switched to the SoftSwitch using the gateway as indicated on the following figure.

In this case the R1.5 interface disconnects from the TDM Switch and connects to the VoIP gateway that is connected to the SoftSwitch via the SIP data communications network.

Migrating SIP subscribers to PSTN via R1.5 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 R1.5 interfaces the gateway on the TDM network side looks as the R1.5 subscriber node while on the IP network side it looks as the IP PBX where IP subscribers register (please see the figure).

The best advantage is price, because it’s less than competitors have. So the same function, but lower price – the best choice.

R1.5 (CAS) Protocol conversion option

Since the gateway supports SS7, DSS1, QSIG, V5.2 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 R1.5 interface protocols.

R1.5 СAS 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.

Technical Specifications

Network Interfaces
TDM	up to 16 E1 interfaces
SIP and RTP	up to 480 VoIP channels, 10/100/1000 BASE-T Ethernet
Management	Fast Ethernet, RS-232

Signaling Protocols
IP	SIP, SIP-I, RTP, RTCP, TCP, UDP
PSTN	SS7, ISDN PRI (DSS1, QSIG, Q.931), QSIG, V5.2, R2 MFC, R2 CAS, R1.5

Feature Support
Voice codecs	G.711 (a-law, µ-law), G.723.1, G.726, G.729a/b, GSM
Voice processing	Adaptative programmable jitter buffer, VAD, SID, CNG
DTMF	RFC2833, SIP INFO, RFC 2976
FAX	fax over G.711, T.38 fax relay
Echo Cancellation	G.168 up to 128 ms
Registration and Authentication	up to 10000 SIP-subscribers
Registration	SIP-trunks
Call Routing	TDM-SIP, SIP-TDM, TDM-TDM and SIP-SIP

Power
	Single/Dual-redundant 220 VAC or/and 48/60 VDC Input
	Up to 28W Power consumption (for 16 E1)

Operations Management
	GUI via Embedded Web Server
	SNMPv2 monitoring
	Syslog Telnet (for CLI)

Security
	Integrated firewall, Password protected access, SSH, RADIUS login

Operating Environment
Operating temperature	from 0°С to +60°СHumidity
Humidity	up to 80% at +25°С

Hardware
System Type	Board
Dimensions	1U high, 19″ wide rack mountable

Delivery Set

SIP/E1 Gateway Lite:

• SIP/E1 Gateway Lite (1Е1, 30 SIP channels, G.711, T38 codecs, echo cancellation G.168)

SIP/E1 Gateway:

• SIP/E1 Gateway (2Е1, 240 SIP channels, G.711, G.726, G.729, T38 codecs, echo cancellation G.168)
• SIP/E1 Gateway (4Е1, 240 SIP channels, G.711, G.726, G.729, T38 codecs, echo cancellation G.168)
• SIP/E1 Gateway (8Е1, 240 SIP channels, G.711, G.726, G.729, T38 codecs, echo cancellation G.168)
• SIP/E1 Gateway (12Е1, 240 SIP channels, G.711, G.726, G.729, T38 codecs, echo cancellation G.168)
• SIP/E1 Gateway (16Е1, 480 SIP channels, G.711, G.726, G.729, T38 codecs, echo cancellation G.168)