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|   E1 Analogue Channel Banks with Voice Detection   |

|   PRODUCTS   |

Comarra's intelligent E1 Channel Bank, VCL-CB-INT™ provides Voice Activity Detection (VAD) activated "answer supervision" and "disconnect supervision" to connect VoIP, VoFR and VoATM networks to analog PSTN (POTS) lines that do not provide any type of answer supervision / battery reversal functions. Also available with PRI ISDN (Euro ISDN) Q.931 interface (optional).

The interface to the analog PSTN (POTS*) lines have been ruggedized to provide complete protection against line card failures which occur from induced voltages from AC power lines and lightening strikes and difficult field conditions.

The intelligent E1 channel bank can be used for VoIP, VoFR and VoATM network communications that will terminate traffic directly to the analog PSTN lines. The channel bank solution provides a cost-effective platform to convert upto 30 dial-up, analog (PSTN) voice circuits to a digital E1 interface to connect to VoIP, VoFR and VoATM Gateways.

Comarra's years of experience in providing telecom transmission solutions to customers worldwide, located in over 80 countries, has been build in to providing a cost-effective - yet an intelligent E1 channel bank solution.

The VCL-CB™ E1 Channel bank offers all types of analog interfaces including FXO, FXS and 2W/4W E&M interfaces, that may be required to connect to an E1 digital interface of a VoIP, VoFR and VoATM Gateway.

The E1 Channel Bank shall interface to the E1 port of any Server / Switch / VoIP Gateway / PBX using R2 CAS (R2 Digital) Signaling  (R2 Channel Associated Signaling) as per ITU-T Q.421 / Q.422 recommendations, to connect up to 30 analog interfaces to an E1 port.

VCL-CB-INT  E1, Channel Bank
Switch / Server / VoIP Gateway Application

The cable plant of most telecom service providers is not designed to deliver E1 services to customers in most parts of the world. The VoIP Gateway / Switch / Server / PBX with an E1 interface, thus, in such cases can only be accessed through dial-up, 2 wire analog lines, the only available link for connecting the Exchange (Central Office) to the Corporate PBX Networks and VoIP Gateways.

Comarra's VCL-CB™ intelligent E1 Channel Bank is especially useful in countries, where the cable plant is not equipped to deliver digital E1 services to the customer, who are using the next generation access equipment, which can only connect to an E1 interface.

The E1 Channel Bank solution is available in two versions:

The first E1 channel bank VCL-CB-BR™ provides answer supervision when the called party answers, upon receiving an actual battery reversal of the PSTN analog line.

Both, the line connect and disconnect functions are provided using the actual battery reversal function of the PSTN analog line (e.g. much like your coin pay-phones).

Available with FXO, FXS and E&M interfaces

The second E1 Channel Bank VCL-CB-INT™ is an intelligent E1 Channel Bank that provides the metering function using Voice Activity Detection (VAD) to provide voice activated "answer supervision" and "disconnect supervision". The VCL-CB-INT™ intelligent E1 Channel Bank uses a sophisticated DSP algorithm to "listen" to the PSTN line for "voice activity" and will provide "answer supervision" information to initiate the metering process.

The VCL-CB-INT™ E1 Channel Bank is available with FXO interfaces which shall connect to the analog PSTN (POTS*) lines from the local Exchange / Telco / Switch.

* POTS: Plain Old Telephone Service:

Features and Highlights

  • Used for terminating long distance traffic on PSTN lines that "Support" or "Do Not Support" "Battery Reversal / Polarity Reversal" (Answer Supervision).
  • Uses sophisticated DSP algorithms to provide Voice Activity Detection (VAD) to provide "Answer Supervision" to initiate metering and "Disconnect Supervision" feature to "Disconnect hung / stuck PSTN lines".
  • Ruggedized equipment design.
  • Provide complete protection against the line card failures occurring from induced voltages from AC power lines and lightening strikes and other difficult field conditions.
  • VF (Voice Frequency) specifications are in accordance with G.712, ITU-T recommendations to provide clear voice.
  • Ideal for traffic termination for corporate and ISP customers, who wish to connect their fully digital networks to the PSTN, through the available analog dial-up PTT lines.
  • Ideal for connecting to PSTN.
  • Also used in conventional applications to deliver voice over an end-to-end E1 (radio / fiber / HDSL) links.
  • Available with FXO, FXS and 2W/4W E&M customer interfaces.
  • Compliance to all the relevant ITU-T recommendations.
  • Modular, 3U high, compact construction provides easy maintenance.
  • Plug & Play - easy to install equipment.
  • Extensive set of alarms.
  • Available with easy to use Windows™ based Graphical User Interface.
  • Synchronization to different user selectable clock sources.
  • Remote Access through TCP/IP (for remote configuration and monitoring - available as an optional extra).
  • Available with an E1, 2Mbps interface or a fractional E1 interface (to even start service with less than 10 lines).

Ordering Information for VCL-CB-INT intelligent E1 Channel Bank

Core System Composition: (Common Equipment) Part No.#
19-Inch Chassis with connectorized backpanel VCL-CB-000 / 005
-48VDC Power Supply Card                     VCL-CB-010
E1 Interface Card (Control Card) VCL-CB-015-INT
User Interface Cards
FXO (Central Office Interface Card) VCL-CB-030-INT


FXO interface cards - connect to the analog PSTN (telco) lines.
FXS interface cards - connect to analog telephone sets.
E&M interface cards - connect to E&M switches / interfaces.

Others Links:

  STM SDH Multiplexers
  E1 VoIP-GSM Gateways
  VoIP SS7 and C7 Solution
  Echo Cancellers and VQE Solutions
  GSM Gateways / GSM Channel Banks
  E1 and T1 over Ethernet (TDM over IP)
  Digital Access Cross Connect Switch (DACS)
  E1, T1, E3, DS3, Ethernet Converter (IP over TDM)

Technical specifications are subject to change without notice.
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