...it did this before on the local copper lines too.
That means that any discussion about changing voltages from channel banks is moot.
That means that there is something amiss in the alarm panel.
Have the alarm installer meet you at the site, wire in a known-working POTS line that has 48 volts on it, and see what happens.
Is the alarm panel programmed to expect to see 2 dial tones? Most commercial systems want both lines to be powered in order to operate correctly. Since you indicate that there is only one line (which is a violation, of course) try installing a second POTS line (or even a line from the channel bank) and see what happens. Or put the same dial tone on both RJ31X jacks just as a test.
Please keep us posted.
Last edited by Arthur P. Bloom; 05/02/13 06:11 PM.
