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Clarification of return loss

You previously wrote,"If there is a large distance between the caller and the sender or if the return loss is too great, the echo becomes audible and a big pain!"

Actually, the greater the return loss the better. It is a measure of the loss of echo, hence the term "return loss." The following is from BICSI TDMM 10th edition: "The power of the reflected signal is called the return loss (R) in dB and is derived from the reflection coefficient. The better the impedance matching, the lower the reflected energy and the higher the return loss. Return loss (R) in dB = 10 log (ρ2)"

Sorry to nitpick, but there is a great amount of misunderstanding regarding the issues of cabling.

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The intent of the statement was that if the return loss is outside of acceptable ranges, there will be issues. I was not referring to the measured db of the return loss, just how far it is outside of the parameters.

You are correct and thank you for helping me clarify this issue. Unfortunately, there are a lot of networks out there that suffer from poor installations and terminations. This will keep the cable plant from passing testing or supporting real-time services. I am amazed at the number of companies that either do not test or randomly test their installations.

There are also problems with some installation companies testing with old revisions of testing software and gear. This further compounds the problems.

Early VoIP installations and even newer ones can fail due to improperly installed infrastructures. It is very important that all testing parameters (based on the latest addendums) are addressed. Thanks again for helping to clarify my intent!

This was first published in May 2005

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