[cisco-voip] ATA-187 and Ground? (Jason Aarons (AM))

[Jerry Ridge]

It could be that you have a resistive short on the wire.  You can test for that with a meter or toner. If you notice a toner will short and the tone will stop, or the light on the toner may glow dim. It's a dumb test but quick and dirty. It may be the tone will be muted still there but at a low volume.
The other thing that could cause this is capacitance on the wire. The only way I have seen that removed is with something called a load pot, which is a coil to ground.
It could be your wire is in water and needs to be direct burial type of wire or jelly filled.  
If you had a ground on the line you would hear a hum. If you have a bad ground at the power suppy or a bad filter in the power supply you will hear a hum. 
The way to test for capacitance is with an analog meter and when you hook it up or revers the leads you will see the meter kick.
You could try replacing the ATA with a known good one and see if the ATA is doing it, itself. 

JeRy 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20130824/9f60c5b7/attachment.html>