Q factor: the wrong answer for service providers and equipment manufacturers

This article discusses a particular alternative to the long-term BER test and is an attempt to stimulate debate about the value of this alternative method until an accurate universally acceptable option is developed. Understandably, telecommunications industry players want an acceptable method that can determine error ratios faster than the traditional BER test can. One alternative to emerge thus far is quality factor, or "Q factor," testing, which basically can be used to calculate the theoretical BER of a transmission system. This "quick and dirty" test in fact provides a small incremental benefit in that it saves time. However, some network operators and network equipment manufacturer (NEM) installers are discovering that Q factor, for a variety of technical reasons discussed, can be an inconclusive measurement of BER. Consequently, some who use Q factor testing may base their operational decisions and hence their competitive position in the market on misleading assumptions.