advancements in telecommunications technology pose increased
challenges in providing customers with broad bandwidth transmissions
at the speeds they expect within the local loop. With the
development of new technologies such as xDSL, more data is
being transmitted at faster speeds. Thus, ensuring the integrity
of that data has become increasingly important. Considering
that twisted pair copper, which was originally designed for
only analog (voice) transmission, is still being used as the
media for these faster and more voluminous data transmissions,
several key issues arise.
Twisted pair is not the best medium for the volume and speed
demands being experienced in the pipeline today, let alone
the limitations it will place on emerging data transmission
network architecture. However, the cost for complete replacement
of twisted pair in the pipeline by other media such as coax
or fiber isn't feasible in many installations. The true challenge
becomes developing new transmission data formats that will
work faster with either twisted pair or fiber. These new data
formats would provide for the continued use of existing twisted
pair installations, which are prevalent in commercial and
residential facilities, and allow for the flexibility of future
conversion to fiber. Until then, testing of twisted pair copper
is still a primary concern.
To ensure the integrity of the data speeding across the phone
line, proper installation, qualification and maintenance of
the network, from the backbone to the home or business is critical.
Periodic testing of the line is required to assure continued
transmission accuracy. Essential tests include cable and transmission
testing of the physical layer to verify its capability to transmit
analog or digital signals; protocol analyzer testing to monitor
the traffic on a network and to determine that it conforms to
the expected protocols; and wireless communications testing
of mobile/cellular base stations and mobile phones.
A variety of general purpose and specialized test instruments
and accessories have been developed for cable, transmission,
protocol, and wireless testing. From general purpose analog
meters for POTS (Plain Old Telephone Service) testing to specialized
instruments such as DSL, ISDN and SONET testers, a variety
of equipment exists to provide the technician with the tools
to perform comprehensive testing of the various layers in
A broad assortment of cable and connector types have been
designed to interface the instrument to the physical media.
Examples of copper-based connections include RJ11¸ RJ45,
RJ48, Bantam, WE310, 5-Pin Protector, BNC, Mini WECO, Standard
WECO, and 66/110 Block adapters/interfaces. There is also
a wide variety of multi-pair cable assemblies, such as Front
Tap Shoes with Bendix or Cinch-Jones connectors, for testing
a large number of twisted pair lines. Each of these is designed
to provide easier access to the test signal.
the appropriate test accessory can make the difference in
how easily and efficiently the technician can complete the
task at hand. For example, Pomona provides a wide selection
of test accessories designed for use in both the Central Office
and OSP (OutSide Plant). Some of these include patch cords
and adapters with Bantam (DS1), WECO 310 (DS0), and coaxial
75-ohm BNC/Mini WECO/Standard WECO connectors. A complete
family of piercing alligator test clips, primarily for use
in the field, allows the technician to quickly access twisted
pair lines with minimal risk of wire damage. Pomona's offering
includes eight piercing Alligator Test Clip model configurations
to meet a variety of multi-purpose test requirements, including
piercing wire sizes from 14 to 26 AWG (Figure #1). One of
the newest piercing clip styles features a "row of points"
configuration that is attached to a banana or bantam plug.
With fewer piercing points, the "Row of Points"
clip minimizes wire penetration and reduces the likelihood
of breakage (Figure 1). Other
types include a "bed-of-nails" style for small wire
penetration (Figures 2 and 3), and single-needle style for
penetration of wires with heavier insulation (Figure 4). All
styles, with their wire piercing capability, eliminate the
need for insulation stripping and splicing, significantly
reducing test time for the technician.
Other accessories like the Mini WECO, Standard WECO, 75 Ohm
BNC (DSX-3) coaxial cables and adapters, Tel-Line Tester,
and Universal DSX-3 kit, are used primarily for testing in
the Central Office and OSP. Again, choosing the best tool
for the job at hand can make the difference. For example,
the technician can use the DSX-3 test kit to test, monitor,
patch and cross-connect circuits while eliminating the need
for multiple cables, optimizing testing efficiency. Another
example is the Tel-Line Tester, which plugs into 5-pin protectors
and eliminates the need to strip or splice wire. To troubleshoot,
the technician simply clips a buttset or voltmeter to the
appropriate metal tabs and checks the switch to determine
whether the problem is located in the field or at the Central
Office without having to cut and strip wires to isolate the
providing significant time-savings. A wide assortment of
patch cords and cables with various breakout terminations
such as alligator and Minigrabber® test clips, and RJ48
plugs, are also available to meet a variety of testing needs.
factors figuring into the equation for improving test accuracy
include the type of test accessory itself. Nickel-plated Bantam
and WE310 test plugs reduce oxide build-up that could affect
signal integrity. Accessories manufactured from molded plastic
housings provide strain relief for durability and shielded
cables protect signal integrity.
While agreement on the importance of proper testing to ensure
data integrity is probably not the issue, how this is accomplished
can mean the difference between a difficult or simple test
job and the degree of accuracy achieved. The biggest advantage
to choosing proper test accessories is that it makes the technician's
job easier and faster, with more accurate results.