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Community Member

Incorrect billing on FXO ports

Hi Pros,

I have a client who is using extensively analog lines connected to FXO ports to make PSTN calls.

Whenever they dial any PSTN number, the IP phone starts displaying "connected seconds" even though the service provider is playing ringout or any messages.

This is also causing incorrect billing generated via billing software with CDR generated bills coming to more than 25% of actual PSTN bills.

The customer is using CUCM 6.1.1 with H.323 SRST router with analog lines connected to it.

Please advise if there is a solution to correct this.

Hall of Fame Super Gold

Re: Incorrect billing on FXO ports

Since with FXO it is impossible to know the exact time you are connected, the timer starts as you complete selection.

If you want accurate connect/disconnect times, use ISDN, not analog.

Re: Incorrect billing on FXO ports

That is not correct about FXO in general. What the OP needs is called answer supervision and should be provided by telco. Combined with proper configuration, IOS level, etc. on Cisco side this should work fine. Here is some info about answer supervision on Cisco gear:

-- please remember to rate and mark answered helpful posts --
Hall of Fame Super Gold

Re: Incorrect billing on FXO ports

You will find that in most countries outside N.A. no additional services for analog lines are available from telco. Meaning, no ground start, no answer supervision, tone-only based disconnect supervision, no analog DID.

In general, my replies are adapted to the region I recognize the OP coming from, so in this as in many other cases, no digital lines = no love.

Community Member

Re: Incorrect billing on FXO ports

Hey Brandon and Paolo,

Thanks a lot for your invaluable input. Next thing for me is to check with Cisco and UAE service providers whether they support answer supervision and if yes their frequencies/cadence values.

And Paolo, I agree with you..I hate the deadly combination of FXO-analog and CCM/CME but no option but work it out!

Hall of Fame Super Gold

Re: Incorrect billing on FXO ports

Deadly is about right. Good luck!

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