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ISE Columnist Don McCarty, OSP Expert

Challenge your team to test their knowledge of the copper infrastructure

Dec. 1, 2016
Together, Vernon May (a DSL trainer) and I think this last column of 2016 is a good opportunity to test your knowledge of the copper infrastructure. If you’ve read our […]

Together, Vernon May (a DSL trainer) and I think this last column of 2016 is a good opportunity to test your knowledge of the copper infrastructure. If you’ve read our columns regularly this year, you should have a leg up on acing this test. If you’ve taken our copper cable infrastructure and/or DSL training, you better get all the answers right! (Answers will be in the January 2017 column, and available online then, too, at

The first group of questions addresses the health of the copper infrastructure. Before installation of any service the cable pair should be tested to assure that it is a clean cable pair with good longitudinal balance. Then, and only then, should the circuit be connected.

Copper Infrastructure Questions
1. When testing the cable pair, the digital multi-meter shows a 150 k ohm ring ground using the resistance bridge feature set to 24 gauge on the technician’s multi-functional test set shows a distance to the fault of 700 feet. The cable map shows 300 feet of 24-gauge cable to a splice and the rest of the cable is 22 gauge. How far into the 22-gauge section into the fault?
a. 250 feet
b. 460 feet
c. 640 feet
d. None of the above

2. Testing several cable pairs in a section of PIC cable with a DMM indicates crossed battery on ring conductors only. Tip conductors test clear >999 Meg ohms. The open meter shows a measurement that is longer than the section length. The root cause of the section failure is:
a. Water in a splice or encapsulation
b. Water in the section
c. Sheath damage
d. All of the above

3. Testing a cable pair with a DMM the cable pair shows 999 Meg ohms tip to ring, tip to ground, and ring to ground. The longitudinal balance is 58dB. The open meter shows 3,800 feet tip to ring, 5,000 feet tip to ground, 5,000 feet ring to ground. No sync. The root cause is:
a. Bridged tap
b. Load coil
c. Split cable pair
d. None of the above

4. Sheath bonds should be torqued to:
a. 40 inch lbs.
b. 30 inch lbs.
c. 20 inch lbs.
d. None of the above

DSL Questions
1. Digital Subscriber Line (DSL) technology is most like
a. Ethernet
c. ATM
d. All of the above

2. Bits per Bin (or Tone) indicate
a. Noise at Frequency
b. Attenuation at Frequency
c. Transmit Power at Frequency
d. All of the above

3. Downstream Bit Rates are generally higher than Upstream Bit Rates because
a. The Upstream bits have to fight gravity
b. More Downstream bins are allocated than Upstream bins
c. The Upstream bits must travel through a different filter than the Downstream bits
d. All of the above

4. Physical Copper Problems can impact
a. Modem Sync
b. Bit Rates
c. Circuit Reliability
d. All of the above

5. High AM Radio Noise Combined with high Power Influence indicates
a. Too many radio stations in your area
b. Sheath problems
c. Power Network Issues
d. All of the above

6. A defective modem can cause
a. Wireless Issues
b. DSL Issues
c. Ethernet Issues
d. All of the above

7. A good DSL port sync test at the DSLAM can hide
a. A weak port that will cause Rate/Reach DSL Bit Rate Issues
b. Ethernet Issues
c. Provisioning Issues
d. All of the above

8. Which fault more negatively impacts DSL service at 10 Ohms?
a. A high resistance open
b. A tip to ring resistance fault
d. A tip to ground or ring to ground

9. Good DSL Sync, but no IP address indicates
a. A provisioning problem
b. A DSL problem
c. A Copper problem
d. All of the above

10. Good attenuation, good noise readings and low bit rates indicate
a. A defective modem
b. A bad splitter
c. A bad port
d. All of the above

11. When both US and DS bitrates are negatively impacted equally, it is an indication of
a. A defective modem
b. A bad port
c. A physical problem
d. All of the above

12. When there is no obvious root cause to a DSL problem, the first stop should be
a. At the Main Frame
b. At the DSLAM
c. At the Cross-Connect Box
d. At the NID
e. At the Jack

13. Impulse noise can be caused by
a. Power company issues
b. Subscriber home wiring issues
c. Neighborhood home wiring issues
d. Appliances
e. Light Fixtures
f. All of the above

Signing off
The end of a year and the beginning of a new one causes me to reflect on what was good and not-so-good. What’s always good is knowing someone (at least one someone) is reading my columns! I often get feedback, and that helps me decide what’s important to people and, therefore, what to write about. So, please keep the emails coming — and I wish all of you a wonderful 2017! Send an email to [email protected] or text or call 831.818.3930. For information on copper infrastructure training, including DSL and noise, contact Susan Cain at email [email protected] or call her cell phone at 408.393.4794.

Vernon May has leveraged his 35+ years of service provider and vendor experience into that of trainer/coach, inventor, systems designer, program manager, product manager, and plant operations expert. He holds 2 US Patents, including #8,027,807 B2 on Remote DSL Circuit Evaluation. If you have questions about your DSL, contact him at 254.979.4749 or email [email protected], or visit Vernon May Solutions LLC at

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