OSP Expert: Don McCarty

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…

Bandwidth Demand


I received an email from Todd who is the Plant Operations Manager of a fine independent Telco. Don, We are replacing copper with fiber but can’t do it fast enough to keep up with customer demand, with the growth of the IoT the demand for speed is now!!! We have started to bond copper to get additional speed to these customers but we have some concerns. 1. We understand we need to keep our cable fill ratio to 50% or less — is this correct? (Can we increase this when bonding?) 2. When bonding, are there specific pairs we need…

The unknowns that make fault locating in sections of buried telephone plant difficult.


Most bad sections of buried copper plant are a slam dunk to fix, especially when the well-equipped and well-trained technicians are given time to find and repair the root cause of section failure. These buried sections are usually in the distribution plant, and they are usually 25-pair or 50-pair PIC cables. They have failed because of sheath damage, splice or encapsulation failure. It is usually fresh trouble if there are no prior complaints from the customer. First, when trouble-shooting a bad cable pair, the skilled technician using a multifunction test set that includes a resistance fault locator (RFL), an open…

Electric Fence Interference


I received a question from a field technician about electric fence interference. He shared that he had a case of trouble that included noise on the telephone circuit emanating from an electric fence in the area. He said that the line is free of DC type faults. He was wondering if it could be a grounding issue? In some 50+ years in the telephone business, I have dealt with the effect of electric fences on voice grade circuits, bandwidth circuits, and even rarely, circuits where the customer is fiber fed. Once the cause of disrupted service is proven to be…

A Hitch in the IoT


In 2019 I see the IoT expanding at an alarming rate, and I project that the infrastructure will fail to keep up with the demand. More things are communicating with more things over the wired infrastructure, the wireless infrastructure, fiber infrastructure, and, yes, the coaxial cable infrastructure. If there is a disruption of any of the infrastructures, then the IoT is affected. Any down time on any of the 4 structures will have both immediate and long-term effects on the IoT.  Concerns Network reliability is all important. My concerns are many.  My first concern is the oldest copper infrastructure which…

Using the earth-gradient test set when fault locating in buried plant


Around 1976, a fine gentleman by the name of Tom Lathrop, then with Bell Labs, invented the earth-gradient method of fault locating. Using a transmitter, an earth contact frame, and a receiver, transmitted voltage differences are detected and shield-to-earth or conductor-to-earth faults are exactly pinpointed in buried plant. Two test sets were manufactured by Western Electric, one for cables, one for drops. And finally, the difficult world of buried fault-locating was made simple. Several manufacturers build similar devices, and they all use the same principle as Tom’s sets. Today’s earth-gradient test sets work on any cable or drop that is…

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