T1 Quad Echo Canceller
Upto 32 T1 Echo Cancellers per Shelf / Chassis

The Echo Canceller solution offers carrier-grade voice quality per AT&T Voice Quality Assessment Lab. The Echo Canceller supports fax / modem G.164 and G.165 (2100 Hz) tone disable function.

Signaling

The T1 Echo Cancellers support the following signaling protocols supported:

• 24B (24 Voice Channels) with out-of-band signaling.
• C7 / SS7 Signaling on any user selected time-slot.
• 23B+D, PRI ISDN (23 Voice Channels+D Signaling Channel).
• Robbed Bit Signaling.
• All signaling options are USER SELECTABLE / USER CONFIGURABLE.

Redundancy

The Echo Canceller is equipped to offer redundant power supply (optional)

Remote monitoring and control

The equipment offers RS232 serial interface for configuration through a PC COM Port and an Ethernet (10BaseT) interface for remote LAN configuration and monitoring which allows the user to monitor and configure the equipment over a TCP-IP network, from anywhere in the world over a TCP / IP network.

Types of T1 Echo Cancellers offered
User Selectable:

• 128ms - Unidirectional (cancels the echo with upto 128ms. tail at the far end).

• 64ms - Bidirectional (cancels the echo with upto 64ms. tail in both directions).

Quad T1 VCL-EC^TM Voice Echo Canceller - Technical Highlights

• Provides voice echo cancellation of up to 64ms. Bidirectional / 128ms. Unidirectional - User Selectable / User Programmable.

• Meets ITU-T G.168 (2000 / 2002) requirements for echo cancellation.

• Signaling protocols supported: 24B (24 Voice Channels) with out-of-band signaling (C7 / SS7 Signaling on any user selected time-slot). 23B+D, PRI ISDN (23 Voice Channels+D Signaling Channel). Robbed Bit Signaling. All signaling options are USER SELECTABLE / USER CONFIGURABLE.

• The Echo Canceller supports fax / modem G.164 and G.165 (2100 Hz) tone disable

• Offers RS232 serial interface for external PC COM Port and Ethernet (10Base-T) interface for remote LAN

• Non-Linear Processor with Comfort Noise Insertion

• Automatic by-pass upon power supply failure / removal of power supply
  Redundant Power Supply (Optional)

Fault Recovery

The Echo Canceller equipment offers fault recovery feature. It offers automatic by-pass upon power-supply failure / removal power supply. (i.e. it offers T1 circuit by-pass in the event of power supply failure).

Applications for the Quad T1 VCL-EC

Datacomm Applications

• Voice over Frame Relay

• Voice over ATM

• Voice over Internet/LAN (VoIP)

Central Office and PBX Applications

• Network Trunks.

• Echo Canceller Pool.

• Common Equipment.

• Audio Conferencing Bridges

Voice Over ATM Applications

• A multi-channel echo canceller resource or pool is shared among many channels to reduce cost.

• Echo cancellation is done at a DS0 level.

Satellite Communications Applications

• Digital Circuit Multiplication Equipment (DCME)

Wireless Applications

• Digital Cordless and Cellular Basestations.

• GSM, CDMA.

• Access Controllers.

Voice Over Frame Relay, ATM Applications

• Frame Relay and ATM routers and switches introduce large, variable and unpredictable delays.

• Echoes from the Public Switched Telephone Network (PSTN) in combination with the delays from Frame Relay and ATM equipment yield objectionable speech quality.

Quad T1 VCL-EC, T1 Echo Canceller Advantages

USER PROGRAMMABLE tail-side. Echo cancellers are always required to be installed, such that, the tail-side of the echo canceller always faces towards the source of the echo. Our T1 Echo Cancellers have a USER CONFIGURABLE tail-side so that the user may remotely change the direction of the tail-side of the echo canceller - without having to physically change the T1 connections on the echo canceller card.

USER PROGRAMMABLE Signaling Option. Our echo cancellers provide USER PROGRAMMABLE T1 signaling options . The T1 signaling protocols that we support are 24B (24 Voice Channels) with out-of-band signaling (C7 / SS7 Signaling on any user selected time-slot). 23B+D, PRI ISDN (23 Voice Channels+D Signaling Channel). Robbed Bit Signaling. All signaling options are USER SELECTABLE / USER CONFIGURABLE.

Quad T1 VCL-EC, T1 Echo Cancellers Support 2100 Hz fax / analog data modem tone detection and echo canceller disabling on all channels. For dedicated digital data or video channels, if you wish to assign certain specific times-slots of the T1 circuit for dedicated video you may do so, using our T1 Echo Cancellers. Our T1 Echo Cancellers allow the USER to PROGRAM / ASSIGN dedicated time-slots for digital data or video transmission. The user may specify / define the dedicated data channels so that they are always bypassed from the echo cancellation circuitry - leaving those dedicated time-slots for digital data communication / dedicated video transmission only.

USER PROGRAMMABLE dedicated data channels. The user may specify / define the dedicated data channels so that they are always and completely bypassed from the echo cancellation circuitry - leaving those specifically assigned dedicated time-slots for digital data transmission (including video transmission).

Features and Highlights

• User Selectable - 128ms - Unidirectional or 64ms - Bidirectional. The user selection is made through a user configurable software interface command.

• Compliant to ITU-T G.164, G.165, G.168 2000, G.168 2002) requirements.

• Carrier-grade voice quality per AT&T Voice Quality Assessment Lab.

• Fax / Modem G.164, G.165 - 2100 Hz tone disable as per ITU-T G.164/G.165 Recommendations. Allows fax and analog modem data transmission through automatic echo cancellation enable / disable function.

• Disable Tone detection supported on all audio paths.

• Fully integrated independent 24-channel voice echo canceller

• Option for user to select data or voice channels for selective echo cancellation. This feature allows the user to use selected time-slots for data transmission to enable digital data / CCS signaling transmission.

• Transmission (data mode), while keeping the echo cancellation "ON" on the remaining time-slots (voice mode), on which echo is required to be cancelled.

• T1 Circuit by-pass in event of power supply failure. This feature enables the by-pass of the T1 Circuit in the event of power failure. This ensure continues signal even if the power to the echo canceller fails.

• T1 Circuit by-pass on power failure.

• T1 Circuit by-pass on Echo Canceller card removed. This feature allows the user to by-pass the T1 Circuit by simply removing the echo canceller card.

• T1 circuit connects "through" as soon as echo canceller is removed from its slot.

• Non-Linear Processor with adaptive suppression threshold and comfort noise insertion

• Programmable Double-Talk detection threshold.

• Narrow-Band signal detection.

• Adjustable Gain/loss settings on all channels. Provides the user the flexibility to adjust and optimize the voice and transmit receive levels.

• Path change detect permits fast re-convergence when a major change occurs in the echo channel.

• Signaling Support:

  • 24B (24 Voice Channels) with out-of-band signaling

  • C7, SS7 Signaling

  • 3B+D, PRI ISDN (23 Voice Channels+D Signaling Channel)

  • Robbed Bit Signaling (on any user selected time-slot)

  • All signaling options are USER SELECTABLE / USER CONFIGURABLE.

• Redundant Power Supply (Optional)

• Non-Linear Processor with Comfort Noise Insertion

• TCP / IP remote access for remote configuration and control.

• Assures operability with V.32 / V.32bis / V.34 modem and fax transmissions. Conforms to standards assuring proper public network operation and facilitating system integration.

• Removes residual echo and minimizes switching effects thereby providing high perceived speech quality. Unique design provides the industry's best sounding single chip echo canceller.

• Ensure echo canceller maintains excellent performance at all times in the presence of non-echo voice signals. Useful for trunks that have very low echo-returns loss.

• Ensure echo canceller maintains excellent performance at all times in presence of tones or signals including DTMF tones.

• Instability detector suppresses variable pitched ringing or oscillation.

• User selectable tail-end side. This feature allows the user to select the "Tail-End" side of the Echo Canceller. The "Tail-End" side of Echo Canceller is that part of the network which generates / causes to generate the Echo. Unidirectional Echo Cancellers must always be installed on far-end of any network from the point at which an Echo is being heard. The "Tail-End" side must always face the "Source Side" of the network which is generating the echo. Ideally suited to handle most echo situations.

• Usable in telecommunications systems worldwide. Able to interface in most systems where linear samples are available.

Front View of the Shelf

Application Diagrams

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