I'm trying to dig up the "rule of thumb" value for what a telephone company would consider acceptable path loss when they run a new line out to a customer. I spent a lot of time in digital telephony but the number for a regular voice line is eluding me.

I'd always considered 3-4dB to be the number, but some of the articles I'm pulling up are saying 5.5dB to even 8.5dB as within spec. This seems to be an awful lot of loss which would translate to quiet audio. I know the actual path loss varies with the length of the loop, but there are typical and maximum values that I'm trying to find.

Does anyone have any rules of thumb or experience in this area? What is the typical path loss of a telephone line and at what level of attenuation will a telco actually do something to remedy the situation?

  • \$\begingroup\$ Try pushing the volume up button on the side of your cell. That seems to work for me :) \$\endgroup\$ – Kevin Vermeer Aug 12 '10 at 18:25

According to this document, from a company that sells circuit loss testers, telephone companies are required to provide -8.5 dB (relative to a 0 dB 1 KHz test signal). However it says "generally speaking, anything below a -7.5 gets hard to hear", and "the ideal db loss to look for is -5.5db."

  • \$\begingroup\$ Wow so it really is about 5.5dB... that's quite a bit of loss! \$\endgroup\$ – akohlsmith Aug 14 '10 at 0:53

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