Can there be line noise outside the audible range that results in my ISP's server dropping the connection, and applying a continuous tone, as soon as the handshake has been completed?
Background: I typically connect at 46.7-48.0 kbps. REN on the line is <4. I had to call out the telco repair guy when 60 Hz noise suddenly appeared on the line and my connection speed dropped as the noise got louder.
When "fixed" by the telco all the 60 Hz noise had gone, but a low-intensity low frequency continuous hum had appeared. It might be a harmonic of a signal I can't otherwise hear. From that moment my ISP drops me as soon as I connect, without even attempting to shuffle down through the speeds.
The telco denies all responsibility. I'm going nuts. A little Radio Shack "noise eliminator" does nothing.
What do I do next?
BTW two computers with different configurations and modems are behaving in this manner, and I have connected directly at the consumer interface, thereby disconnecting all phone wiring in the house, in case it was acting as an antenna. And yes, the low hum is definitely incoming.