ISE Columnist Don McCarty, OSP Expert

Maintaining the copper infrastructure coverage until it is replaced by fiber

June 1, 2017
The PSTN, or POTS, network may be at the end of its life, but the copper infrastructure properly maintained continues to generate revenue from special access circuits to homes and […]

The PSTN, or POTS, network may be at the end of its life, but the copper infrastructure properly maintained continues to generate revenue from special access circuits to homes and businesses for years to come.

In 2015, the FCC released new data claiming that there was over $40 billion in broadband and data service revenues known as special access. The majority of special access service is still mostly copper-based services, and that revenue-generating copper infrastructure is paid for. To date, only 25% of the homes and businesses in the US are fiber-served. Fiber is deployed as fast as it is economically feasible in any area, but in the meanwhile, existing copper infrastructure must be proactively maintained until that area is economically fiber-served.

Reactive maintenance is counterproductive, resulting in costly unnecessary truck rolls and repeated complaints from dissatisfied customers that abandon service if any alternate bandwidth vendor is available. The reactive process is to move the customer’s circuit to another cable pair (cut to clear) until there are no other "clean" cable pairs left to provide service. Eighty percent (80%) of the field technician’s time is spent working on the effect of the service failure rather than the root cause.

Alternatively, proactive maintenance strives for root cause, and when the root cause is identified, located, and repaired, the satisfied customer’s service is restored on that cable pair. In proactive maintenance, there are root causes of service failures that affect both copper and fiber cables. In some instances, the cable has to be replaced.

Most circuit failures are single pair failures. That one cable pair has failed affecting only one customer.  No other cable pairs around that pair have failed, and no other customers are affected. The root cause is usually hands in the plant. The fault is usually in a buried pedestal or an aerial terminal. A multi-functional test set will indicate what the fault is with its digital multi-unbalance. Then, using the test set’s resistance fault locator, open meter, and/or Time Domain Reflectometer (TDR) to show the distance to the fault, a skilled field technician can clear most single pair faults in less time than it takes to transfer the circuit to another cable pair.

When testing the cable pair with the test set’s DMM, any crossed battery tip or ring to ground indicates multiple faults to the cable. Any time multiple faults are tested and identified, the root cause should immediately be located and repaired to prevent further truck rolls and service interruptions.

Multiple faults traced to aerial terminals and buried pedestals are usually caused by animals, insects, or physical damage. If the damage was caused by rodents, then safety is in order. Wear a mask and use disposable gloves when fixing the faulted pairs to protect against Hantavirus Pulmonary Syndrome (HPS). While the technician is there, any pedestal or terminal repair is in order. In buried pedestal, pea gravel is a must. If insects are the root cause, repellent can be applied.

Thorough section analysis is in order if multiple cable pairs prove to be faulted between pedestals in buried sections or between poles in aerial sections. This is where both the reactive manager and the reactive technician
are somewhat at fault. A business case is in order if the section of cable needs to be replaced. Keep in mind that the field technician is time-sensitive, and it takes time to build a quality business case. I have looked at over 2,000 faulted sections of buried cables in my 50-plus-years career that were already up for replacement, and over half of those sections were restored by digging 1 or 2 holes in the section and repairing a wet splice or sheath damage in the section. There is only so much money allocated to section replacement.

Root cause or causes of section failure are:
Water in a section of aerial or buried air core PIC cable (replace ASAP)
• Water in a buried splice or encapsulation (Local knowledge and a quality business case will determine if it is more economical to repair or replace.)
• Sheath damage (Local knowledge and a quality business case will determine if it is more economical to repair or replace the section.)
• Phase power or lightning damage (If faulted in one place repair. If multiple places are damaged or if the impedance of the cable has changed replace the section. If multiple sections are faulted a business case for fiber is in order.)
• Squirrel and woodpecker damage to sections of aerial cable (Replace with alternate jacket material or cover with squirrel guard for both copper and fiber cables.)

A well-maintained copper infrastructure has provided, and will provide, the funding to get us into a fiber or a infrastructure for future broadband services.

Signing off
We need your input! Tell us what is causing problems for you and your customer, and we’ll see if we can help. Contact me at [email protected] or 831.818.3930. If you have DSL issues and concerns, contact Vernon May at [email protected] or 254.979.4749.

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