Round 4
This column is the 4th in a series about test sets. I began by writing about the 965 — an industry favorite that will no longer be produced. Then I moved to a few of the test sets that are excellent replacements including: the Megger HT1000/2, the JDSU HST3000, and today I write about the EXFO MaxTester 635. If you asked which of these 3 is best, I could only answer that each of them is an excellent option and which is best depends on your specific needs: The capabilities of the techs using it, the most common and the most complex outside plant challenges; anticipated growth; the technology changes you think you will need to address; together with budget limitations.
EXFO MaxTester 635
This test set is a multi-functional tool for any service provider deploying multi-play services over single-pair or bonded ADSL2+ and/or VDSL2 circuits. My interest in the test set is focused on using the copper-testing features for provisioning and maintaining the copper infrastructure for bandwidth.
I have been working with the MaxTester 635 for a while, both on my own and while training with my clients who have purchased this set. First, it is feature-rich and goes beyond the copper infrastructure (my area of interest) and into xDSL performance verification. In some cases, I think this may be more than many techs need. However, there may also be many companies where techs would benefit from these features, or may need them in the future depending upon what’s expected of the company’s technicians.
It tests basic twisted pair quality. It can identify and locate faults, and troubleshoot noise and signal issues to determine if the cable and cable pair is capable of supporting xDSL technology. It uses noise measurements, longitudinal balance test, and power spectral density tests to assist in provisioning and maintaining the copper infrastructure.
This test set is well purposed for traditional narrow band (POTS) active and vacant pair testing as well. Its easy-to-use menus make it a good tool for installation and repair technicians and cable maintenance technicians. The test set has the traditional copper measurements.
When testing vacant cable pairs the following tests are available:
- Voltage detects AC RMS and DC voltages on the line.
- The longitudinal balance test tests the resistance and capacitance balance of the vacant cable pair.
- Resistance uses DC current to measure the resistance when testing tip to ring, tip to ground, and ring to ground. It is used to identify possible faults and to identify series resistance using a resistive balance test.
- A soak test will allow up to 500VDC to be applied to identify any short or ground. The soak test will also break down galvanic corrosion.
- A capacitance test measures the capacitance of the cable pair to find open cable pairs and is also used for estimating loop length.
- A spectral density graph will indicate any interferer or disturber of bandwidth. Interferers such as AM radio, ham radio, or short wave radio usually indicates bonding issues.
- The resistance bridge, open meter, and the Time Domain Reflectometer (TDR) will locate DC type faults.
The Active POTS auto test looks for:
- AC Voltage RMS
- DC Voltage on active pots line
- Loop or line current
- Station ground resistance
- Circuit loss
- Circuit Noise (metallic noise)
- Power influence
- Longitudinal balance
It features good fault location capabilities, from the TDR testing to Resistive Fault Location (RFL) testing. The TDR can be run in auto-mode for new users to TDR to get quickly up to speed or can be placed into manual mode for those techs that like to get their hands dirty in the art of TDR testing. In cases where high resistance faults exist, its resistance bridge feature offers 2 and 4 wire (single pair and separate good pair). Technicians have the option of running single-ended tests or running tests against a far end device (FED).
This test set excels in relation to wideband testing. ADSL2+ and VDSL2 are impacted by frequencies outside of the voice band, so it is absolutely mandatory to test the frequencies that you are deploying to. Many broadband operators are using VDSL12 or VDSL17 to provide customers with multi-play services, and these multi-play services can be impacted by external noise. This test set offers spectrum analysis of (PSD noise), near-end crosstalk (NEXT), impulse noise and attenuation analysis testing.
In addition to DSL, this test set offers users the ability to connect up to the network via Ethernet. Whether DSL or Ethernet, this test set allows techs to test higher layers applications such as Ping, FTP, and offer web browser capabilities over DSL or Ethernet. For operators offering IPTV and/or VoIP, this multi-function test set allows for emulation of the Set Top Box (STB) for join/leave testing and the ability to place and receive VOIP calls. Various statistics are collected for all these higher layer tests.
This test set offers a comprehensive solution for those operators looking to replace their discontinued 3M 965 product. From traditional volt/ohm testing, to voice band testing through to wideband copper testing and then into VDSL2 vectoring and bonding, the MaxTester 635 from EXFO has you covered.
My final comment is that the 300+ page manual demands patience and dedication from the tech or great training from the rep or company. IMHO, it’s not a user-friendly manual.
Signing off
In my next column, I will move beyond my discussion of multi-functional test sets and write about the AALogic D-105 Construction Test Set. If you haven’t done so, consider joining the LinkedIn group, Copper Infrastructure and Outside Plant Technical Challenges. Get involved in discussions, learn, and help other techs out. Contact me for questions, comments, and thoughts: [email protected]; 831.818.3930.
