OSP Expert: Don McCarty

Resistance Bridge Fault Locating


or the fallacy of single-pair hookups — Over my many years in the business, I have written and taught about resistance fault locating (RFL) using the single-pair hookup to find a ground or crossed battery on one side of a cable pair when the other side tests clear. Regular column readers and my past students know that I’m adamant about this topic because without a good process, in-depth knowledge, quality tools, and management support allowing the needed time to implement the correct repair, technicians will cut-to-clear rather than locating and repairing the problem. This approach, while easy and fast to…

Letters From Readers


May 8, 2019 Power Influence and Balance — While I always find Don McCarty’s articles to be very informative and spot on, in his article in the May issue of ISE magazine, I think there could have been a better way to describe the relationship between power influence, noise metallic and (pair) balance. While what Don said is true: “Circuit noise (noise metallic) and power influence are interrelated, each being dependent upon the other to form acceptable balance”, I think the better way of explaining this would be as follows: “Power influence and balance (pair quality) are interrelated, each being…

Don’t give up on the tough cases of power influence and circuit noise


My colleague Russ Gundrum and I helped Sam, a fiercely dedicated manager, solve a problem that several technicians were unable to resolve — and they gave up. The customer had so much noise on her line that she was unable to hear or talk; without a cell phone, she was left without a connection to the outside world. When the problem was resolved, she actually cried. Neither Russ nor I collected a dime and yet we agreed this was the best compensation we’ve received in our decades of solving trouble cases. We were honored to meet this manager who was…

Those Special Cables


Troubleshooting low count cables and drops with today’s test equipment — I received an email from a field technician about a problem he was having with the fault location features of his multi-function test set when using the RFL, Open Meter, and TDR functions. He stated that the measurements were fairly accurate when using the manufacturer’s settings on cables that were 25-pair cables and larger. When measuring the distance to a fault using the manufacturers settings on small count cables such as a 6-pair cable, the measurements were inaccurate. Field technicians use many types of test equipment or multi-function test…

The Bane of the Unnecessary Truck Roll


I received this email from a retired field technician who is also a POTS and bandwidth customer of a large RBOC that he worked for. Donald, I’ve been reading your column for what seems to be 20 years. Always good stuff.  I was formerly an outside plant field technician, facility technician, and testing technician for a large RBOC. After an injury from a fall from a telephone pole that ended my career as a field technician, this led me to working at a rather prestigious space facility that has no aerial plant. My stint there lasted 14 years working and providing technical…

Fault Locating the Copper Infrastructure for Bandwidth With the Advent of IoT


The ongoing expectation of extended, reliable and quality bandwidth has always been a maintenance challenge for field technicians and that challenge has increased exponentially with the addition of IoT services. While fiber-to-thehome is the ideal solution for delivering bandwidth, for now, many residential customers depend on copper as the final step in supplying high-end services including IoT. Field technicians get dispatched on a myriad of problems to restore service, especially on bandwidth circuits that are fiber-to-the-node (FTTN). They are responsible for the cable pair, the drop, inside station wire if applicable, Wi-Fi, modems and other end user equipment. In the…

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