Validator vs. Traditional Certifiers

So what is the basic difference between the Validator certifier and traditional certifiers? It is that the traditional certifier uses frequency sweep signals to measure likely conditions for failure on a cable and measures the results of these signals against a set of pre-determined limits on each measurement (the metrics of TIA568). The Validator uses digital signal generation to measure the actual noise levels on a cable run, Signal-to-Noise ratio (SNR) and adds the BERT test as a demonstration of error free transmissions of actual digital data over that line. In effect, our BERT test is an advanced version of the PSFENEXT measurement mentioned in TIA568. It sees actual data flow rates from BOTH ends of the cable run while Far End NEXT and Power Sum NEXT try to infer data carrying capability by simulation with transient frequency signals. The BERT result is a true measurement of real data flow and error levels and with this in mind it is easy to see that the Validator does match all of TIA568 test specifications, since the SNR contains all the noise measurements of TIA568 and the SKEW measurement is the same. We just do the tests with a different method. In fact, we maintain that the digital BERT test is a more accurate measurement of return data loss than the FENEXT and PSNEXT tests called for in TIA568.

What does the Signal-to-Noise Ratio shown in Validator test results represent? Remember that this is a compilation of measurements off of the Gigabit Ethernet Transceiver. They include Return Loss, Attenuation, NEXT and Channel Response from all four pairs which is necessary to measure noise for Gigabit. The PASS/FAIL level of 20dB is a correlation off of the Ethernet Transceiver chip which was arrived at by analyzing cable failures in all types of environments and conditions. This chip was tested and measurements correlated by the University of New Hampshire Commercial Network Test Laboratory that is the gold standard for all network equipment manufacturers. We took the same PASS/FAIL levels from these tests and applied them to the software/firmware programs we created for the Validator. The correlation of data is every bit as valid and accurate as a $6,000 traditional certifier.

Remember that the higher the SNR is the better the level of signal over the ambient noise on the line. You might think of it as the bars on a cell phone, the more bars the higher the signal strength. The same goes for the SNR measurement that shows up on the results screen of a cable test. We put the upper limit as 30dB that is an almost perfect propagation level for any type of data cable. This limit is displayed at the top of the SNR bar on the Test Results screen at every cable test.

Our SKEW measurement is a way of showing if there is any delay on any pair in getting data to the other end at a different rate than the other pairs. SKEW causes loss or dropped data bits and can “confuse” network equipment. SKEW is measured in nanoseconds (ns) and a SKEW of more than 45 nanoseconds is bad. This is the same level of failure that is called for in TIA568/570.

Both of these measurements, SKEW and SNR, have roots in TIA568. They provide the data for a first look at a cable and let’s us know if some physical impediment exists before any data can flow. Noise and signal delays can usually be traced to bad terminations or improper cable installation. Even poor quality components will cause failures. However we use these measurements as only a tripwire. The BERT test is the real test of cable functionality.

BERT itself was a bit of trick for us to adapt to the Validator. We had to obtain and test every PHY or Physical Interface Link on the market today to make sure that our return information would match acceptance formats for these PHY chips on various brands of network equipment, routers, switches, hubs, etc. We did this to make sure that when we certified a cable at Gigabit speeds the data transference rate that was measured would work with installed equipment, no matter who the manufacturer is. This was possible, since there is only about a half dozen PHY chip manufacturers in the world.

Our innovative and technologically advanced approach shows that this is an entirely different way of addressing the need to determine whether or not a cable can carry data at a given speed. Traditional certifiers infer and we use actual conditions that interface with actual network components. It is that simple.