I'm in need of Phone line quality testing from a party other than Verizon (in NYC).
I have customers who I suspect has phone line quality issues, but Verizon just listens to the line and says there's no static and says everything is ok.
Are there any professionals or specific tools that can detect issues with a phone line that is used for modem connections? What are they called? Who do I search for? Any experience with them?
Basically the situation is that we have clients that authorize and settle credit card transactions over dial up modem... and they fail frequently over one phone line.... and never over another.