Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

CCM 4.1(3), FXO call billing


I have CCM 4.1(3),CAR 4.1 and IOS 12.4 with 14 FXO loop-start lines on 3845 platform.

Now problem,

1)when a person from PSTN line call to us he is getting started bill even before our Operator(Attendant console) goes off-hook.

2) Similarly when a user from call Manager calls out CDR records shows that his billing starts even before PSTN user pickup the line.

3) Further about CRA billing, How do I can bill local call and national call with differently as both are billed in different rate?




Re: CCM 4.1(3), FXO call billing

You may be having an issue due to the FXO as well as the fact that the FXO voice-ports are also MGCP controlled by the CCM.

1. Use E&M - If possible, use E&M connections between routers and switches/PBXs. E&M

inherently provides better answer and disconnect supervision. I am not telling you to buy

E&M. I am merely pointing out that E&M is another option.

2. Use ground-start signaling - Use ground-start signaling on the FXO port of the router

and configure the PSTN switch to provide a ground-start connection. If it is available,

the switch will remove ground from the connection when the call finishes (disconnects) and

the FXO port will go on-hook. Use the command "show voice port" to see if the FXO port is

configured to ground-start or loop-start signaling. Your FXO are using loop-start.

3. Use Power Denial - Have the router's FXO port respond to Power Denial. Power Denial is

a ~600msec interruption of line power that can be generated by some PBX's and some CO's.

The FXO voice interface card detects that power is no longer present and interprets this

as a supervisory disconnect. This is the signaling looked for when "supervisory

disconnect" is configured on the voice-port (default configuration). Power denial must be

configured on the PBX/Telco also.

Voice-port 1/0

Supervisory disconnect

This command indicates whether supervisory disconnect signaling is available on the FXO

port. Supervisory disconnect signaling is a power denial from the switch lasting at least

350 milliseconds. When this condition is detected, the system interprets this as a

disconnect indication from the switch and clears the call. You should configure no

supervisory disconnect on the voice port if there is no supervisory disconnect available

from the switch.

New Member

Re: CCM 4.1(3), FXO call billing

Thanks a lot,

It seems power denial works fine. Anyway it also take one o two ring to disconnect. But it is fine.

Do you have any idea of billing at different rate for local calls and national calls using CAR.

CreatePlease to create content