TN464HP DS1 interface, T1 (24 channels) or E1 (32 channels)
The TN464HP circuit pack provides:
The echo cancellation capability of the TN464HP is selectable on a per-channel basis. The TN464HP DS1 interface automatically turns off echo cancellation when the interface detects a 2100-Hz phase-reversed tone generated by high-speed modems (56-kbps). But the interface does not turn off echo cancellation when the interface detects a 2100-Hz straight tone generated by low-speed modems (9.6-kbps). Echo cancellation improves a low-speed data call. The TN464HP DS1 interface is intended for customers who are likely to encounter echo. This echo can be over circuits that are connected to the public network. The occurrence of echo is higher if the switch is configured for ATM, IP, or other complex services and interfaces to certain local service providers. These local service providers do not routinely install echo cancellation equipment in all their circuits. A common source of echo is "hybrid" circuits, where conversions between 2-wire analog circuits and 4-wire digital circuits take place. The TN464HP DS1 interface cancels echo with delays of up to 96 milliseconds.