ch is a physical port on a switch or access facility into the nearest wire center. In addition to the key field data, detailed unit count and pricing for all fixed monthly charges and all variable or usage based charges should be extracted and carried over into a file in the organ- izational accounting system. In addition to the charges for service, 11 MANAGING COST OF EQUIPMENT FACILITIES AND SERVICES taxes and other fees such as access charges and universal service fees should be extracted and maintained in the file. Essentially what has to be done is to take this file with the current charges and perform all the calculations done by the telephone company and re-create the same information, but instead of using the reference pricing they used, use a separate reference database that will be created in steps 4 through 8 of Table 11-2. Figure 11-2 is a conceptual diagram of the invoice validation system. It must be implemented in the organization's information technology (IT) infrastructure or built separately and integrated with the other systems. The functions in this concept are intended to accomplish steps 1, 2, and 3 outlined in Table 11-2. Note the dotted line from vendor Service Information Pricing Calculation Price Calculation Taxes Tax Calculation Information Fee Calculation Transfer Extract Billing Summary By Dept/Cost Center, Fixed and Variable Charges User, Location By Location and Number Service and Amounts Taxes and Amounts Vendor Approved Fees and Amounts Pricing Cost Data Location Phone Number FIGURE 11-2 Telephone Billing File Interface to Enterprise Accounting System PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS pricing. It will become solid after completion of the standard cost development in steps 4 through 8. Resist temptation to jump too far too fast until you're confident the following functions are being performed: Import the billing file Extract the desired data Compare the data from the reference file with the billing file and highlights exceptions Output a list of inv