Modem tester targets future
ADSL standards and deployment

The HP Asymmetric Digital Subscriber Line (ADSL) test solution from
Hewlett-Packard (Palo Alto, CA) is offered as the first manufacturing test
system for ADSL modems. Although ADSL technology is still in the pilot
testing stage, market research firm Frost and Sullivan (Mountain View,
CA) expects that the market for ADSL modems could increase at a compound
annual growth rate of more than 70% over the next seven years.

Primarily focused on high-volume manufacturing, the HP ADSL solution
meets current ADSL and plain old telephone service (POTS) standards (ANSI
T1.413 and ITU T0.133, respectively). It also supports carrier amplitude/phase
modulation and discrete multitone technologies.

Consisting of VXI/GPIB hardware and dedicated software, the system interfaces
with either the HP 79000 FCT functional-only communications test platform
or the HP 3079 CT platform, which is used for both functional and in-circuit
testing (see Fig. 1 ). Up to four modems or channels in parallel
can be tested concurrently.

Fig. 1. Interfacing with the HP 79000 FCT or
HP 3079 CT communications test platforms,
the HP ADSL is the first manufacturing test
solution for ADSL modems.

Three primary tests–parametric, transmission (BER), and digital I/O–are
performed (see Fig. 2 ). The system's test modem acts either as an
ADSL transmission unit at the central office end (ATU-C) when testing an
ADSL transmission unit at the remote end (ATU-R), or as an ATU-R when testing
an ATU-C. The test modem sends ADSL signal traffic or activates ATU-R modems
for transmission and parametric testing.

Fig. 2. The HP ADSL system performs BERT, digital I/O, and parametric
testing.

Comprehensive parametric and transmission testing is performed by the
ADSL virtual instrument (AVI). The AVI is a parallel-test virtual instrument
built on a POTS virtual instrument with enhancements for the higher-frequency
testing (6 Mbits/s) required for ADSL. Interoperability, BERT, data/voice
separation, interference, and distortion tests are performed by the AVI.

Digital I/O, ATM, backplane I/O, and alternative subscriber protocols
are tested via the backplane emulation and serial-interface testing and
emulation modules. Correct data transfer via subscriber/network connections,
backplanes, and digital interfaces is verified at this stage, as is testing
for interconnect shorts and opens.

The HP ADSL solution is available now for the HP 3079 CT platform with
prices from $275,000, and is expected to be available next month for the
HP 79000 FCT with prices from $250,000. Prices for pay-per-use solutions
for lower-volume testing start at $150,000. The HP ADSL solution is configurable
to specific testing needs as well as to future ADSL standards as they become
finalized. For more information, call Hewlett-Packard at 800-452-4844, ext. 5600, or visit
http://www.hp.com/go/tmdir.