Voice Over IP Router – Viper

Voice Over IP Router-Viper
Voice Over IP Router-Viper Front View

Office-to-office: Many primary rate ISDN circuits today are used for PBX networking using a multiplexer to allow data from a router to share some of the bandwidth. This is an inflexible solution requiring multiple units with expensive and inefficient permanently allocated bandwidth.

A solution with ten voice channels plus 128 Kbps for data would require a 768k fractional Pri link.

An equivalent Case Communications Viper solution would require only a 256 Kbps link, resulting in a significant saving in recurring line rental costs. It would also allow 150Kbps to 256Kbps for data depending on the number of active channels.

Voice Over IP Router-Viper Typical Application

Voice Over IP Router-Viper Application

Mixed Networks

Viper units networked together act as a distributed exchange allowing multi-channel Pri-Connections at the central site with a mix of Bri, AC15 / DC5 or even standard POTs phones at remote sites. Viper networking converts the different interfaces and protocols.

Viper Technology

Viper incorporates ITU – G.729A voice compression at 8 Kbps, which with silence compression and confort noise generation allows a reduction to less than 1 Kbps during pauses in the speech.
The standards based header compression scheme ensures that the voice packets occupy only 9600 bps of the WAN bandwidth. Automatic fragmentation of datapackets where necessary and prioritisation of the voice ensures the quality of service (QOS) aspects needed for voice. Viper incorporates an IP/IPX router with multiple interfaces including ISDN Bri and serial synchronous WAN connections for Frame Relay and leased access, plus a serial port for HDLC pass through. The ISDN Bri can be used for 128 Kbps dial-up connectivity or for top-up/ backup on leased circuits. The PABX connection is via a multichannel Bri / Pri Interface.


  • Quality of service (QoS) – The Viper ensures voice QoS by fragmenting IP packets and prioritising the voice. This is difficult to guarantee in other voice over IP products which do not have an integrated router.
  • Cost-effectiveness – Viper single-box integration reduces capital costs by removing the need for separate router and voice units, and provides ongoing savings in line rentals through converged networking as well as reduced installation, maintenance, support and administrations.
  • Improved quality– The digital voice connections on the Viper eliminate the losses and interference possible with analogue connections. Standardised digital Bri and Pri interfaces and their associated protocols ensure maximum compatibility and reliability. A single multi-channel Pri ISDN connection eliminates the multiple interfaces and cables required with analogue interfaces all contributing to the quality of the Viper solution


WAN servicesPPP & ML-PPP
Frame relay
HDLC (pass through (HDLC Over IP)
WAN optimisation
STAC compressions
ISDN back-up with bandwidth on demand
Prioritisation plus fragmentation of data packets
Voice and header compressions
RIPv1, V2
Frame relayFRF 1.1
FRF 3.1
ITU Q9.922
Ethernet Interface10 Base TWAN interfaces2 channel X.21 / V.35
2 Channel RS 232 / V24
Protocols and servicesIP Routing
IPX Routing
ISDN WAN interfaceSingle Pri and Bri
2 x 64Kbps Bri Channels
PABX interface4 port – Dual Bri 4
8-10 port Pri & Bri
Local control port
Voice codecsITU G.711
ITU G726
VBR with silence suppression
Voltage range210 – 240 vac 50/60 Hz @ 15 VA
48 vdc
Fax supportGroup 3
2400-14400 BPS
SafetyTUV EN60950
CSA 950
EN5022 FCC Part 68, FCC part 15
ApprovalsNet 1.2.3
CE Mark
Fax supportGroup 3
2400-14400 BPS

Case Studies

Network Rail


Tetra Wireless Over IP


Ordering Information

ViperEU 300 – Viper Assembly 230 vac
EU 300-24vdc – Viper Assembly 24 vdc
EU300-48vdc – Viper assembly 48 volts DC
EU 320-E1 – Viper with Primary rate ISDN trunk 230vac
EU 320-24vdc – Viper with Primary rate ISDN trunk 24vdc
EU 320-48vdc – Viper with Primary rate ISDN trunk 48vdc
Trunk Interface modulesEU 305 – Dual X.21
EU 306 – Dual V.35 Board
EU 3075 – Dual E1 PIM 75 ohm board
EU 3072 – Dual E1 PIM 120 Ohm
Voice ModulesEU 301 – E&M / AC 15 4 port Module
EU 302 – 4 port FXO / FXS Module
EU 303 – Pri board – 10 simultaneous calls
EU 304 – 2 port (4 calls) Bri Voice Module

Additional Information

Case Communications Serial port and VoIP Router – Viper Data Sheet

Case_Viper_Manual rev 2.1

For more information please contact Case Communications.