[asterisk-users] Help 60Hz Hum?

[Philip Prindeville]

Jay R. Ashworth wrote:
> On Fri, Oct 12, 2007 at 11:09:59PM +0200, F6HQZ wrote:
>   
>> Check if you have a ground loop.
>> If yes, this is probably the cause of this hum.
>> Open the loop.
>>     
>
> Actually, hum involving analog POTS lines is usually the result of the
> line becoming unbalanced to ground.
>   

Or else running your phone wiring in parallel with and too close to 
electrical (line voltage) wiring, resulting in induction (crosstalk, as 
it were).