High-speed traffic from the DSL links is groomed and concentrated for efficient forwarding to backbone data switches and routers. Once the line has initialized, the service provider knows the maximum data rate for that line and can offer varying levels of service based upon the maximum line speed. Line data rates can also be set manually to meet specific service levels. The first card slot in the base chassis contains an MCC card to manage the entire stack. Up to six chassis can be stacked in total, providing scale up to 68 DSL ports.
All chassis contain an integral fan and power supply.
Any combination of AC and DC can be used for redundant operation. Every ATU-C card has four transceivers on board, each connected to a single xDSL line. The IP data card provides concentration onto a 10Base-T output. The frame relay data card and DS0 multiplexer card provide concentration onto DS-1 outputs. All DSL and MCC circuit cards are hot swappable and can be replaced without powering down the stack or disrupting the operation of other cards.