The VCL-EC, DS3 echo canceller provides echo cancellation of upto 128ms echo tails (in bi-directional mode), for canceling both near-end and the far-end echoes, in the most demanding network conditions with full voice quality enhancement features.
The echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) requirements for echo cancellation. The echo canceller solutions 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 protocols supported are:
Type of Echo Canceller offered: DS3 Echo canceller
VCL-EC, DS3 echo cancellers are offered to provide cancellation of upto 128ms echo tails. The echo canceller equipment is compliant to ITU-T G.164, G.165, G.168 (2000 / 2002) requirements for echo cancellation.
Valiant offers echo cancellation and voice quality enhancement solutions for the following network situations:
Features and Highlights
DS3 Echo Canceller - Features and Highlights
The echo canceller equipment offers fault recovery feature. It offers automatic by-pass upon power-supply failure (i.e. it offers E1 circuit by-pass in the event of power supply failure).
Remote Monitoring and Control
The echo canceller is equipped to offer redundant power supply (optional).
Unique DS3 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 DS3 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 DS3 connections on the echo-canceller card.
USER PROGRAMMABLE SIGNALING OPTION: Our DS3 echo-cancellers provide User Programmable DS3 signaling options whereby the user may use our DS3 echo-cancellers just as efficiently over a wide spectrum of DS3 signaling options. The DS3 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 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 bu-passed' from the echo-cancellation circuitry - leaving those specifically assigned dedicated time-slots for digital data transmission (including video transmission).
The DS3 echo canceller supports 2100 Hz fax / analog data modem tone detection and echo canceller disabling on all channels.
Question: What is echo tail-displacement (echo tail off-set)
Answer: Echo Tail-displacement (echo tail off-set) is an important feature used in Bi-directional echo cancellation, to make it effective and useful for bi-directional echo-cancellation.
Explanation: Bi-directional (defined as near-end and far-end automatic echo cancellation operation) echo cancellers have the capability of canceling echoes in BOTH directions (on the Transmit as well as the Receive paths), by installing them at a single location. Bi-directional echo-cancellers can be installed at a single location, either the Near-End or the Far-End, and used to cancel BOTH Near-End and Far-End echo-tails, from a single installation.
Usually, satellite links and intercontinental VoIP circuits have fixed network delays which exceed the capabilities of commonly available (192 ms) echo-cancellers for Bi-directional echo-cancellation, thus making them unsuitable for bi-directional echo-cancellation.
Example: An intercontinental satellite or a VoIP link may have a fixed end-to-end round-trip delay of 300 ms, thereby rendering all commonly available echo-cancellers, with even 192 ms echo-cancellation capabilities, ineffective for Bi-directional echo-cancellation.
Using the Echo Tail-Displacement (echo tail off-set) feature, the user may offset and account for the fixed round-trip network delay on the return path so that the echo-cancellation window on the return-path is shifted by 300 ms., so as to allow the Bi-directional echo-canceller to function effectively in BOTH directions and to cancel BOTH near-end, as well as the far-end echo-tails on the return path, even if the echo-canceller is installed at the Near-end in a given network.
Echo Tail-displacement (echo tail off-set) allows the user to program a delay off-set on the return path, so that the user may cancel both near-end and far-end echo-tail with a single Echo Canceller installation. The echo tail-displacement allows the user to compensate for the fixed network delays on the return path of the echo-tail, so that the user can effectively cancel, both near-end and far-end echoes using a single Echo Canceller without being limited by the fixed end-to-end delay of that network link.
Valiant's Echo-Canceller has a user programmable "echo tail-end displacement" (echo tail off-set) from 0 ms. to 896 ms.
This feature allows the use of a single Echo Canceller installation to cancel echo-tails in both directions over intercontinental satellite or VoIP links where the fixed network delays are excessive (beyond and in excess of (example) 192 ms. echo-cancellation capability of the commonly sold Bi-directional Echo Canceller solutions).
Question: My Network has a total of 300ms. end-to-end delay. How can I use a 128ms. Bidirectional echo canceller to cancel, both, near-end and far-end echoes?
Answer: The use of the "programmable echo tail-displacement" (echo tail off-set) feature in our Echo Cancellers allow the user to cancel echoes on the return path even if the network delays exceed 128 ms.
The fixed network delay shall be calculated ascertained and programmed as the "echo tail-displacement" on the return path. This shall allow the user to use a single Echo Canceller to cancel echoes, Bi-directionally, even if the total network end-to end delay is in excess of 300 ms.
The Valiant 128 ms., Bi-directional Echo Canceller solution, equipped with a user programmable " echo tail-displacement" feature is superior than a simple single 192 ms. Bi-directional Echo Canceller solution for canceling both near-end and far-end echoes, even if the fixed round-trip network delays exceed 300 ms.
Data Sheet (PDF)