What Is It?
The Model 404 is a hand-held combination T1 Digital, Datacom and
Wideband Test Set for
the telecom field technician. It is a
digital, full function 1.544Mbps T1/Datacom Tester, as
well as a
full function analog transmission impairment tester. Uniquely
designed with a
touch screen graphical user interface for
extreme ease of use. It is about the size of a small
telephone
book, weighs approximately 3-1/2 lbs. and is powered by an
internal rechargeable
NiMH battery pack with five to six hours
of battery life. It comes standard with a 115/230
VAC adapter or
an optional 12 VDC cigarette lighter adapter. Analog and DS0
tests meet
IEEE standards.
What Does It Do?
The digital test functionality of the Model 404 allows a wide
range of bit error testing on
framed or unframed 1.544Mbps T1
circuits, and Datacom circuits, including V.35, RS232 and
EIA530. As an Analog Tester, the unit provides a wide variety of
industry standard
measurements to accomplish transmission
impairment testing on 2- or 4-wire dedicated or
dial-up analog
circuits. With the Enhanced Digital option, a T1 telephone is
added with
dial, talk & listen capability on any user selected
T1 voice channel. The 400kHz bandwidth
of the instrument makes
it ideal for qualifying metallic digital circuits which use an
analog
carrier such as ISDN BRI ("U" interface) and 4-Wire HDSL
circuits. The unit, of course, is
also ideal for qualifying
voice circuits, which often will carry data modem and fax modem
signals.
How Does It Work?
The Model 404 is ideally suited for the field technician who
must relate to all types of
digital and analog circuits. Datacom
testing provides for emulating either the DTE or the
DCE while
sending patterns and injecting errors. If the T1 line is driven
by HDSL
technology, the wire itself can be tested using wideband
analog testing to 400 kHz, and
the repeaters can be tested with
the extensive BERT capabilities.
What Can It Test?
As a Digital Tester
two TX/RX ports are provided in order to allow bi-directional
drop and
insert testing. The unit can terminate the line
(simultaneous pattern generation and pattern
measurement) or
monitor the line for BERT patterns, ABCD bit status, and SLC 96
alarm
maintenance and message decode. The Model 404 is
compatible with unframed PCM, as
well as D4 and ESF framing with
B8ZS or AMI encoding.
As a Datacom Tester the extensive pattern generation and
detection and the G.821 bit error
rate reporting are available
for V.35, V.36, RS232 and EIA530 interface testing. The Model
404 acts as a synchronous DTE or DCE device and uses either the
DCE clock or its internal
clock to generate and verify patterns
at speeds ranging from 300 BP/S to 1.544Mbps.
The Enhanced Digital option provides VF testing of any user
selected DS0 channel
including voiceband level, frequency, noise
and return loss. Real-time error counters are
augmented by
histograms so that the distribution of errors during a test can
be studied. It
also provides a graphical display of pulse shape
with the standard mask or a user set mask.
The Model 404 is able to perform AutoTesting with the Ameritec
Model AM440 Remote
Test Partner™. The Model 404 is able to test
analog measurements automatically with the
AM440 placed at the
other end of the wire.
