T1 Echo Canceller - Highlights

• Compact T1 ceho canceller desk top version (modem type) - weight < 1 kg.
• Provides voice echo cancellation of up to 64ms Bi-Directional / 128ms Uni-Directional - User Selectable / User Programmable.
• Meets ITU-T G.164, G.165, 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),
  • D4 Robbed Bit Signaling.
  • All signaling options are User Selectable / User Programmable.
• Allows digital data transmission on user-selected time-slots
• The echo canceller supports fax / modem G.164 and G.165 (2100 Hz) tone disable function.
• Carrier-grade voice quality per AT&T Voice Quality Assessment Lab.
• Local access through COM port (RS232 serial port)
• Easy to use text based CLI commands for management and configuration
• Adjustable gain/loss settings on all channels. Provides the user the flexibility to adjust and optimize the voice,  transmit and receive levels
• Non-Linear Processor with Comfort Noise Insertion
• Option for user to select voice echo cancellation or digital-data transmission selectively on each time-slot 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
• Ensure echo canceller maintains excellent performance at all times in presence of tones or signals including DTMF tones
• Fully integrated independent 24-channel voice echo canceller.

Signaling Support

The T1 echo cancellers supports the following signaling protocols:

• 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),
• D4 Robbed Bit Signaling.
• All signaling options are User Selectable / User Programmable.
• Allows digital data transmission on user-selected time-slots.

Management and Control

• Local access through COM port (RS232 serial port)

Unique T1 Echo Canceller Features

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: The T1 echo cancellers supports the following signaling protocols: 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), D4 Robbed Bit. All signaling options are User Selectable / User Programmable. Allows digital data transmission on user-selected time-slots.

USER PROGRAMMABLE DEDICATED DATA CHANNELS: The User my 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).

The T1 echo canceller supports 2100 Hz fax / analog data modem tone detection and echo canceller disabling on all channels.

Applications for the T1 Echo Cancellers

• Wireless: GSM, CDMA, PCS, and Cellular Base Stations.
• Digital Circuit Multiplication Equipment (DCME) : Satellite Communications and Multiplexers.
• PCS, cellular, mobile, and digital wireless systems.
• PBX and central office systems.
• Datacomm: Voice Over Frame Relay, Voice Over ATM, and Voice Over Internet.
• Voice over ATM, Frame Relay or packet switching systems and fax transmissions.
• Central Office and PBX: Network Trunks, Echo Canceller Pool, Common Equipment and Audio Conferencing Bridges
• Voice over datacomm including voice over Internet (VoIP), voice over ATM (VoATM), and voice over Frame Relay (VoFR).

Datacomm Applications

• Voice Over Frame Relay
• Voice Over ATM
• Voice Over Internet / LAN

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

• GSM, CDMA
• Digital Mobile and Cellular Basestations

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.

Application Diagrams for the T1 Voice Echo Cancellers

• Application 1 - Echo cancellers: ATM / Frame Relay
• Application 2 - Echo cancellers: Satellite Link
• Application 3 - Uni-directional echo canceller
• Application 4 - Uni-directional echo canceller
• Application 5 - Bi-directional echo canceller

Related Links

• Echo Canceller solutions - Home Page