New life for the old copper infrastructure —
This column describes causes of service disruption. Upcoming columns will offer easy processes for identifying the location of the fault.
I have been involved in provisioning and maintaining the copper infrastructure for more than 55 years. During that time, I have had the good fortune of working with many managers and technicians who practice proactive maintenance in their quest to provide quality service over copper.
When proactively provisioned and maintained, good old copper will continue to provide service well into the future. Thousands of miles of copper circuits are providing service on a daily basis, AND IT IS PAID FOR!
Less than 10% of all copper cable pairs are in trouble, and the majority of those faults are terminating faults that are in pedestals and terminals.
Successful proactive teams are comprised of experienced and trained management, field technicians, and engineers. Working together, they take the time to chase down those terminating faults rather than transferring the end user’s circuit to another cable pair.
Herein lies the crux: the highly skilled copper folks are retiring in droves, leaving behind many less-experienced techs together with copper-phobic management teams. These management teams want budgets focused on fiber, and they want to get rid of copper as soon as possible.
However, copper is here for a while yet.
Fiber is pricey, expensive to install, and gigabit speed sounds sexy — but how needed is it? Many residential and small business customers don’t need or want to pay for the privilege of high bandwidth. Or the high bandwidth speeds aren’t being delivered as promised. I see neighborhood chat sites rampant with complaints about AT&T and Verizon fiber not delivering as promised.
Meanwhile, new technologies continue to feed the need for bandwidth over copper at a more reasonable cost — IF it’s taken care of properly.
I am not a fiber hater. I think it’s great, and one day it will be pervasive, particularly with companies like Google Fiber doing much of the legwork for the highest speeds.
Take care of today’s copper customers today!
Serving your copper customers now, and in the future with increasingly improved bandwidth, requires that you practice proactive maintenance, train your techs — and retrain often, and give them the right tools.
A proactive field technician should have these tools:
• a multifunction test set with both narrowband and wideband testing capabilities
• a cable locater with an earth frame for path and depth locating and pinpointing earth faults
• a clamp on ammeter
• a torque wrench
Proactive maintenance process for beginners through advanced
First, disconnect the cable pair at the central office (CO) or remote. Connect the multifunction test set to run the auto test. (I prefer to use the MANUAL TEST; the AUTO TEST is a picture in time, and you don’t see changes.)
Now, look at the longitudinal balance.
• If the longitudinal is greater than 60dB, that is a pass.
• Less than 60dB is a fail.
• A pass indicates that there are no DC volts, no ring or tip ground, or ring or tip open on the pair.
• The pair still could have series resistance fault or a split cable pair.
Look for AC Volts.
• From .2VAC to 50 VAC is expected and OK.
• More than 50VAC: this is a safety issue — follow your company safety practices.
Look for DC Volts.
• Tip and/or ring to ground should read 0 VDC.
• Measuring DC volts tip and/or ring to ground adds resistance to your ohms/volt network, and shows an indicated voltage that is less than applied.
• Volt meters should be connected in parallel (tip to ring) not in series (tip and or ring to ground).
• Any unwanted indicated VDC tip and/or ring to ground can be located using the resistance fault locate (RFL) feature on the multifunction test set.
Look for ohms.
• Tip to ring, tip and/or ring to ground should read greater than 20 megohms.
• Any unwanted indicated tip to ring short and or ring to ground more solid than 20 megohms can be located using the resistance fault locate (RFL) feature on the multifunction test set. (The RFL feature will be covered in future columns.)
The opens function measures cable capacitance, and converts the capacitance to feet or meters, based on the capacitance of the cable pair.
Once repairs are completed, test the longitudinal balance again.
• If the pair still fails, look for a split cable pair or series resistance.
• To look for a split, apply tone to the suspect split cable pair and then look for tone on associated pairs in that 25-pair unit.
• The pair that is split with the suspect pair.
• To identify series resistance, place a grounded short on one end, and measure the resistance tip to ring and then tip and ring to ground.
• Tip and ring to ground should measure ½ of tip to ring ohms.
• Any difference shows series resistance on the conductor with more resistance.
I just read your column about ICEP Engineers in the December 2019 issue of ISE magazine.
As a retired ICEP Engineer, I do not think I could have said it better myself. ICEP Engineers have, for the most part, specialized training and test gear to resolve most noise and induction problems. They should be called for help and assistance in complex problems or when the field technician hits a dead end.
I seldom see ICEP Engineers mentioned in articles dealing with noise mitigation. I think your article will help bring light to this group of noise and induction fighters. Thanks!
As a side note, there were Noise Reduction Handbooks published years ago by abc of Telephony and by Wilcom (test gear manufacturer) that had excellent information on noise mitigation. I do not know if they are still available. If they are not, they should be re-issued.
Keep up the good work!
You may always reach out to me to ask questions or help clarify issues for other faithful readers. Text or call 831.818.3930, or email at email@example.com.
PS. I love reading about new technology in any industry. Take a look at Clive Maxfield’s Cool Beans. Here’s a link to a Cool Beans story about dirigibles deploying drones! https://www.clivemaxfield.com/dystopian-dirigible-deploys-delivery-drones/