ISE Columnist Don McCarty, OSP Expert

Field Test Sets for Provisioning and Maintaining the Copper Infrastructure

Jan. 2, 2015
To provision and maintain the copper infrastructure, field technicians use many different test sets from multiple vendors. Field technicians and managers constantly ask me which is my favorite multi-functional test […]

To provision and maintain the copper infrastructure, field technicians use many different test sets from multiple vendors. Field technicians and managers constantly ask me which is my favorite multi-functional test set and I consistently maintain my objectivity and neutral stance. There are always upsides and downsides to each test set — it’s how the vendors differentiate and market their products.

I wish I could take the best features from every vendor’s set and put them in one test set with a simple step-by-step flow chart for using any feature, that would be my favorite, but that doesn’t happen — and for good reason. Vendors look at what the need is and address it, and the need is different from one telco to the next, one area to the next, one budget to the next — so they all have their place

Like many of you, I’ve been accustomed to Dynatel 965 AMS. They had the largest market share so even if this product was perfect or even the best, it’s what we all were used to using. Sadly, the manufacturer has discontinued making the 965. There is a great deal of comfort in the product on my part, starting with the Dynatel 710A resistance bridge when I worked for the Dynatel Corporation starting in 1973.

The 965 AMS was a culmination of test sets including a digital multi-meter, a transmission test set, a resistance bridge, an open meter, a Time Domain Reflectometer (TDR), an xDSL testing feature, and a low- and high-frequency spectrum analyzer.

Competitive vendors have most of the features that are in the Dynatel 965, and they have added other features that are needed for bandwidth testing. The downside is some vendors, including the Dynatel AMS, have added features that are rarely used by the average field technician. Therefore telcos pay for these features that are rarely used, and the additional features can make the product more complex than it needs to be.

When I train field technicians, both in the classroom and in the field, I train on whatever test set the field technician has. This allows me to get technician input along with my own experience when I am out in the field shooting trouble and qualifying circuits.

Features of the 965

I know the 965 is going away but there are many that will be used for years ahead, so I’m going to review the features of the 965, not because it’s perfect but I do think it’s been the industry standard — and telcos will compare new sets with the 965.

My biggest concern, and often the biggest concern for field techs as well, is accuracy with the resistance bridge, open meter, and the TDR functions, especially in buried plant. The 965 AMS is a proven accurate section analysis test set. If the RFL, open meter, or RFL measurements do not compare with sheath footage or sheath meters using the correct settings, it is a problem in the faulted section and not the measurements from the test set.

The second concern is ease-of-use by the field technician. The flow charts for any function on the test set are easy to understand by the average field technician. This is especially important because most field techs do not have an electronics background.

The manual tests are in order, or easy to find. The digital multi-meter works well with exception. The VOM functions are accessible with a push of a button. For example, the red cords, the black cords, and the green cords are connected to the cable pair, and when the #1 blue button is pressed continuous AC or DC voltage is measured. The field technician can then select tip-to-ring, tip-to-ground,
or ring-to-ground.

The maximum voltage that can be measured with the voltmeter is 300VDC and 250VAC. Any higher voltage, AC or DC, is locked out for set protection.

Loop or line current on an active POTS circuit is readily measured at the customer’s Network Interface by pressing the #2 blue button. Then, by pressing the #5 function key the station ground resistance can be tested and verified.

Press the #3 blue key to test for unwanted resistance tip-to-ring, tip-to-ground, and ring-to-ground. The resistance test will compensate for any series DC voltage to give a more accurate resistance measurement. A higher voltage is used in the resistance test to break down galvanic corrosion on cable pairs.

The #4 blue key is a toolbox to view saved test results, perform a self calibrate, an ohms to distance calibrator, to use Internet Explorer, and to upload results.

The #5 blue key is the open meter function.

The #6 key is selected to send identification tone and higher tones for transmission testing.

The #7 key accesses the resistance bridge and the setup on the Dynatel 965 AMS is the easiest of all of the multi-functional test sets. It is very accurate and can measure the distance to resistance faults up to
20 Meg Ohms.

The #8 key gives access to DSL testing. The DSL functions include: DSL Loss, DSL Noise, DSL Spectrum Analyzer, Resistive Balance, and DSL Impulse Noise. Keep in mind that other test sets also have these features.

The #9 key accesses the TDR. It is a good TDR, but I feel that other vendor’s test sets have better TDRs.

The POTS key includes transmission testing for Loss, Noise, and Longitudinal Balance. Transmission testing can be done manually with ease and is an essential part of the Active Auto Test. If unacceptable circuit noise or power influence is identified it is easy to shift to longitudinal balance to determine if the root cause of the failure is a faulted cable pair or a noise mitigation problem.

The POTS test also includes a Load Coil Counter, Caller ID, Ringers, Level Trace, a Kick Test and Voice Band Spectrum Analyzer. The POTS test includes a Kick Test. The test set has an open meter. In my opinion the Kick Test adds no value to the test set.

The Auto Test (0) key automatically performs the following Tests, Active POTS, Vacant POTS, Vacant Wideband and Smart Auto Test. This feature is a plus.

The Talk Set function allows you to use the 965 AMS tester as a talk set on an active line to send DTMF or pulse dialing. Most field technicians do not use this feature.

Next month I will begin looking at "replacement" sets. I hope we can begin a dialog about what features you most want to see in your next test set.

Signing off

Please call me, email me, or text me about your test sets and what you think you will need in the next set when you are in the market. The vendors want to know what you think and so do I! Call me at 831.818.3930 or send an email to [email protected].

About the Author

Don McCarty

Don McCarty is the OSP EXPERT columnist for ISE magazine, discussing the issues around provisioning, testing, and maintaining copper for all services from POTs to IPTV. Don is also president of and the lead trainer for McCarty Products, a technical training and products company training field technicians, cable maintenance, installation repair, and Central Office technicians and managers. For more information, email [email protected] or visit