able and should ACD, the ACD can answer each call and connect it to a service be regularly reviewed to reflect current requirements and call man- person faster than the PABX. The expected payback period is the agement goals. result of dividing the cost of the ACD by the product of the dif- Calls which pass the restriction tables should be analysed for ference in seconds of answering time, the number of calls per traffic patterns, call durations, and other parameters useful to call second and the value per second. If the payback period is short management. This information is derived from the call detail rec- enough, then the cost is justified for the call management benefits ords produced by the CDR (Call Detail Recording) or SMDR the ACD will provide. (Station Message Detail Recording) features of the PABX. The PABX either produces the information in report form directly, 36/4 Call management PABX with Stand Alone ACD Area ACD Area PABXs Network Tandems Figure 36.1 Corporate environment with areas of call management provides the detail to a storage media for off-line processing, or utilisation information produced by the tandem switch the call outputs the detail to an external reporting system through a V.24 management decisions must be made. interface. All of these alternatives and the reports produced from the In the corporate environment, high volume service and revenue call detail are covered in more depth later in this chapter. producing call traffic is handled most efficiently by ACD functions. While the PABX typically provides detailed information for out- The ACD functions are provided by optional add-on features in the bound calls, it can be very useful to capture detailed information for PABXs or by stand alone ACDs. Call management in the ACD is inbound calls also. This is sometimes available as a special service, directed at the equipment, trunk circuits, call handling staff, appli- usually called AMA (Automatic Message Accounting), from the cation groups, and software controls on call handling. The 