Direct Data Stream. A
transmission method for connecting to the
Internet.
Using serial connections to the telco-run fiber optic DDS network from POP to POP, you can get bandwidth aggregated up to 2Mbps. The standard connection method is available in a variety of end point connectors (RJ45 etc) and is unique in so far as it doesn't require a large scale MTU to terminate the connection to the exchange Router. The limitation for this cost saving attribute is the maximum distance of your Router from the exchange - at last hearing was only about 1.2Km.
Similar in some ways to Frame Relay, although it does not offer the "burst" capabilities of Frame, and thus is more suited to dedicated (fixed) bandwidth or redundant connections.
In Australia, specifically Sydney, Telstra offer a world-class DDS service for a moderately significant fraction of the cost of Frame Relay.