Loop Simulator Handy for DSL Testing
Aiding in schools' network and high-speed access installations, Telebyte Inc.'s Model 454 Local Loop Simulator is a compact laboratory and production test unit that precisely simulates the frequency response of the local loop used by telephone companies. It presents an accurate simulation of both the amplitude and propagation delay characteristics of a single, 26 AWG (0.4mm) telephone pair at frequencies extending from DC up to 1.5 MHz. This is the frequency range of ADSL technology, used to provide high speed Internet access over a local loop.
The unit emulates local loops extending up to a maximum of 18,500 feet. For enhanced flexibility, Model 454 is comprised of separate sections that can individually simulate the characteristics of cable lengths of 500 feet, 1,000 feet, 2,000 feet and 3,000 feet. These sections can be connected in any combination to allow simulation in 500-foot increments of any cable length up to 18,500 feet. Tandem connection is accomplished with front panel push-button switches. In addition, by employing multiple units, ADSL modems can be tested in configurations with bridge taps.
Model 454 is completely passive, requiring no AC power, which makes it a very portable tool. It is equipped with two bi-directional ports, supporting both 400 Volt levels and 120 mA DC current. Telebyte, Inc., Greenlawn, NY, (800) 835-3298, www.telebyteusa.com.
This article originally appeared in the 06/01/2000 issue of THE Journal.