Telephone-NID

[Rocco99]

Bad hum on land line, but phones + line work fine otherwise. Disconnected all phones + then reconnected 1 at a time. Each phone still had the hum.

Took working corded phone to NID (outside box) + opened consumer side. Disconnected line from jack + connected phone in order to check on the hum.

No dial tone! Called phone number w/ cell. No RING! Disconnected phone. Connected line back to jack. Closed box.

Went back inside. Connected same phone again inside. Called land line number w/ cell. "Test" land line phone RANG!

Repeated process. Same result.

What gives? The phone rings inside, but not at the NID. And the line insider works if I plug it in back in at the NID.

In the meantime, I can't test the incoming signal for hum if I don't even get a dial tone at the NID.

[HayZee518]

telephone

at the interface outside there is a carbon resistor inline with the jack to your inside trunk line.
if you unplug the plug @ jack outside you are not on the line.
all landlines [other than party lines] use the center two wires [red/green]
the talk circuit is 90 volts dc. the ringing circuit is 110 volts ac pulsating.
check to see if anyone else in your neighborhood has the same hum.
is your interface grounded?