I received this question from one of our readers on maintaining quality plant for Plain Old Telephone Service (POTS) and bandwidth.

Good Morning, Donald,
  Do you know if there are any time studies that compare how much time it takes to work on maintaining existing aerial plant vs. buried plant? Also, do you have any articles that may be relative to changing a POTS-engineered plant design (multiple runs vs. dedicated) into one that can support Broadband? Any information you provide is helpful.
Have a wonderful day,
Susan

Susan,
That is a loaded question. First, due to the demand to restore service, most telephone companies are reactive instead of proactive in their maintenance procedures. That’s their biggest problem. But here are a few other ideas on their fault-locating procedures that cause problems:

Maintaining Your Plant
When a customer complains of a service problem and it is proven to the cable, the first step is to move the customer to another cable pair. I do not have a problem with this if the field technician then pursues the fault, identifies, locates, and fixes the root cause and moves the customer back to the original circuit.

Instead of following this proactive procedure they send the technician on to the next customer complaint. Then, because the root cause wasn’t addressed and repaired, more customers are affected and more circuits are transferred to other cable pairs until there are no more pairs left to transfer to. In a short period of time, 80 percent of their repair forces are working on the effect of the service interruptions, not the root cause.

When your cable plant gets into this shape, don’t even think of bandwidth. You will be lucky to keep the rapidly decreasing numbers of POTS customers. The numbers of unnecessary truck rolls are beyond belief and the management team just doesn’t get it. Their numbers look good, but they are working with a corrupted data base. When you are driving down the information highway looking in your rear view mirror you are going to hit something.

Field technicians do not effectively use their test equipment when locating the root cause of cable faults. Instead, they use two antiquated processes: the divide-and-conquer method, and the part-changing-mechanic method. Both are time-consuming with unnecessary hands in the plant and gallons of wasted fuel and lost work hours.

Divide-and-Conquer Method
When there is a service interruption most good technicians start at the residence. If the fault is proven into the residence it can be fixed with the first technician on site. Inside wiring problems can be identified and repaired. The fast rate and maximum achievable rate can be tested and determined.

When a fault is proven to the cable plant most technicians go to the cross-connect box or remote to prove the trouble into the feeder plant or distribution plant. When the fault is proven to the distribution plant the divide-and-conquers method kicks in. The technician goes half way to a convenient terminal or pedestal and cuts the pair to see which direction the trouble is. The technician goes half way toward the fault and does it again and again until the problem is isolated.

This back-and-forth technique can be eliminated by using a quality test set to electronically isolate with a resistance bridge, an open meter, and a TDR. This proven method of electronic isolation with a properly trained field technician will save time and money plus quickly locate the root cause of the service interruption.

The Part-Changing-Mechanic Method
The part-changing-mechanic method is used when everything is found OK and the customer still complains. The technician first changes out the distribution pair and if the customer complains again the technician changes out the feeder pair. If the customer calls again he changes out the originating equipment in the Central Office or the card at the remote or the DSLAM if it is a bandwidth complaint.

This is costly, and OEs, DSLAMs, and remote cards can be tested before they are replaced. Equipment should be replaced only when it fails the test. Some DSLAM ports are better than others. The port may not properly function at 8,000 feet and have no problem working at 4,000 feet. Test them under load.

Aerial Plant vs. Buried Plant
I really lean toward buried plant in rural distribution. There are fewer hands in the plant and most of the cables are filled. Problems occur at pedestals, and cables are susceptible to rodent damage and digging, but for the most part, most faults occur in pedestals because of activity. Pea gravel in the bottom of the pedestal prevents rodent damage and the pea gravel condenses the moisture.

Aerial cable is susceptible to Mother Nature, squirrels, birds, insects, water in sections of air core cable, hunters, and technician activity, plus the safety concerns with climbing and bucket trucks. Also, engineering is more difficult because of clearance problems.

Engineering Distribution Plant for Bandwidth
First, use filled cable in both aerial and buried applications to prevent water ingress. DO NOT USE 26 GAUGE CABLE. Eliminate load coils and build out networks. Eliminate any laterals (multiple count cables going in different directions) or bridged tap (wire to the field of the customer.)

Finally, for bandwidth, make sure that you have clean cable pairs with no faults that show good longitudinal balance within the reach of that particular service such as ADSL, HDSL, T1, or IPTV, and you will have a satisfied customer.

Signing off
I have a great opportunity for you: call me or email me with your toughest case of trouble, and I bet I can help solve it and then write about it (I won’t mention your name, location, or company if that’s your preference). That’s some serious free consulting time for you and I’m looking forward to a challenge! Contact me at 831.818.3930 or dmccarty@mccartyinc.com. And remember to check out my blog on OSP® magazine: http://www.ospmag.com/columnists/mccarty/talkback.