Digital subscriber line technology is one of the most promising broadband solutions, despite deployment challenges that have required expensive line-diagnostic equipment and truck rolls. While the remote-deployment model promises greater DSL coverage, it moves line diagnostics out of the central office where it's easier to install, monitor and maintain line-testing equipment. In fact, many have wondered whether remote deployment would cure or kill DSL.

Now line-diagnostic capabilities can be added directly to DSL data pump silicon, with tremendous implications for a deployment environment so challenging that it's estimated as many as 50 percent of DSL hookups fail on the first try, at an approximate cost to carriers (and, ultimately, consumers) of $450 million to date. Embedded provisioning can solve critical DSL deployment challenges while pushing the service out to more subscribers via remote-deployment terminals. Future enhancements could enable carriers to eliminate even more-if not all-of today's total DSL provisioning and maintenance costs of nearly $20 per port.

RISC-based transceiver architectures and low-power, single-ended broadband signal-processing advances make it possible to implement these critical test capabilities as software solutions that reside directly on the DSL data pump silicon.

The first technology to make this possible is available, and combines advanced spread-spectrum radio frequency and other wireless transmission techniques with statistical correlation to create an optimized, low-power version of time-domain reflectometry (TDR) technology. It works without compromising DSL's reach or performance using a low-amplitude broadband signal that does not disrupt service the way TDR's spectrally incompatible pulse can. Statistical correlation reconstructs a clear image of the reflection, with potentially greater accuracy than standard TDR.

Incorporating DSL-provisioning software into DSL data pump silicon provides the foundation for many future capabilities, such as improvements to the existing test suite and the incorporation of voiceband testing. The concept can also be used for monitoring traffic over the DSL modem's access link to assist carriers in capacity planning.

These and other resources will become important as carriers move to the remote-terminal and digital loop carrier-based deployment model, while striving for a higher success rate for DSL service installation. The stakes are enormous, and near-perfect performance may indeed become mandatory if DSL is to survive and flourish in today's difficult business and service-provisioning environment.

Tom Kovanic Is Vice President For Broadband Access At Mindspeed Technologies, A Unit Of Conexant Systems (Newport Beach, Calif.).