I've got four FXO ports on a 3640 router connected to ground-start lines from the CO. Incoming calls work fine, but when trying to dial out the digits somehow get prefixed with a "1"!
For example:
Dial 5551212 and the CO gets 15551212
Dial 14085551212 and the CO gets 1140
-therefore making the calls unrouteable!
Debugs on the router DO NOT show a "1" being dialed, and the CO says there is no way they can be inserting digits. I've tested the lines with a buttset and calls complete normally.
So where is the "1" coming from?
