Advice of Charge

Last Updated : Mar 28, 2022 |

The system supports advice of charge (AOC) on outgoing calls to ISDN exchanges that provide AOC information. It supports AOC during a call (AOC-D) and at the end of a call (AOC-E). This information is included in the SMDR output.

AOC is only supported on outgoing ISDN exchange calls. It is not supported on incoming calls, reverse charge calls, QSIG and non-ISDN calls. Provision of AOC signalling will need to be requested from the ISDN service provider and a charge may be made for this service.  

The user who makes an outgoing call is assigned its charges whilst they are connected to the call, have the call on hold or have the call parked.

  • If AOC-D is not available, then all charges indicated by AOC-E are assigned to the user who dialed the call.

  • If AOC-D is available:

    • If the call is transferred (using transfer, unpark or any other method) to another user, any call charges from the time of transfer are assigned to the new user.

    • If the call is manually transferred off-switch, the call charges remain assigned to the user who transferred the call.

    • If the call is automatically forwarded off switch, subsequent call charges are assigned to the forwarding user.

    • AOC-D information will only be shown whilst the call is connected. It will not be shown when a call is parked or held.

    • Call charges are updated every 5 seconds.  

For conference calls all call charges for any outgoing calls that are included in the conference are assigned to the user who setup the conference, even if that user has subsequently left the conference.  

Enabling AOC Operation

  1. Set the System Currency The Default Currency (System | Telephony | Telephony) setting is by default set to match the system locale. Note that changing the currency clears all call costs stored by the  system except those already logged through SMDR.    

  2. Set the Call Cost per Charge Unit for the Line AOC can be indicated by the ISDN exchange in charge units rather than actual cost. The cost per unit is determined by the system using the Call Cost per Charge Unit setting which needs to be set for each line. The values are 1/10,000th of a currency unit. For example if the call cost per unit is £1.07, a value of 10700 should be set on the line.

  3. Applying a Call Cost Markup It may be a requirement that the cost applied to a user's calls has a mark-up (multiplier) applied to it. This can be done using the Call Cost Markup (User | Telephony | Call Settings) setting. The field is in units of 1/100th, for example an entry of 100 is a markup factor of 1.