Telcordia introduces new test to speed DSL deployment

A modem call determines if a phone line can be a DSL link.

By Tim Greene
Network World, 06/28/99

MORRISTOWN, N.J. - Telcordia has a cure for one of the big digital subscriber line headaches: determining if your phone line can handle DSL.

The company this week will introduce a new service called Sapphyre Loop Qualification Service. The service determines within 5 minutes whether a phone line can handle the digital access technology and the maximum DSL speed the line can handle.

To make those determinations, Sapphyre analyzes the data it gathers from modem calls between the customer site and a Telcordia server. Telcordia says its reading of the lines is 99% accurate.

"If this thing works as advertised, it will be a serious, serious boon [to DSL deployment]," says Mike Lutz, director of product evaluation for DSL provider Darwin Networks.

Trying to determine whether your line supports DSL can be a headache, according to Keith Waldorf, a DSL customer and partner in Web Illusion, a Web design firm in Santa Clara, Calif.

He says some service providers have to send technicians to customer sites to determine if the loop is qualified, while others rely on databases that are not always accurate.

"Even if they work, it doesn't tell you what speed you could get," Waldorf says.

US West !nterprise, for example, has MegaWOT, a database customers can check to see if service is available in their areas and whether their lines can handle DSL. But that qualification is based on maps and records about lines, not a live test.

"The problem [with using maps] is you don't have a real-time measure of the capabilities of the line," says Mike Rouleau, vice president of marketing for US West !nterprise.

Some lines that MegaWOT might reject could be borderline and might actually support DSL, Rouleau says. !nterprise is aware of Sapphyre and weighing whether to use it, Rouleau says.

For the past year, GTE has used its own Digital Services Testing System (DSTS) that combines checks of phone line databases with tests of the line to determine qualification. GTE claims 99% accuracy for the DSTS, but some lines still need technicians to physically check the line.

In addition, some carriers determine whether lines qualify for DSL based on wire length, which Lutz says is not the most accurate way to determine if a line qualifies. A carrier might disqualify loops longer than 15,000 feet, for instance, but an individual 18,000-foot phone line might support DSL depending on the links' individual characteristics, Lutz says. Between 20% and 25% of lines fall into the category of being DSL-capable but outside a 15,000-foot cutoff, he says.

Sapphyre works like this: Interested DSL customers contact the Web site of a DSL service provider to download Sapphyre Loop Qualification software. The software has the customer PC make three modem calls to a Telcordia server. The server analyzes the handshake between the customer's modem and gathers data about echo response, frequency response and packet loss measurements.

Using patent-pending algorithms, the server crunches the handshake data and determines if the line has the characteristics to support DSL. The tests also determine whether the line has load coils - devices that keep voice calls from dying out on long wires and that disqualify a line for DSL.

Sapphyre is available now to service providers. Telcordia says it has customers but declined to name them. The company also declined to say what it would charge carriers for Sapphyre and says it will be up to DSL service providers to decide whether or what to charge customers.

Telcordia is the former Bellore, which did research and set standards for the regional Bell operating companies.

Telcordia: www.telcordia.com