Since material costs account for the majority of PCB costs, all other costs are calculated as a percentage of the material used in the PCB BOM. Cost parameters are shown in Table 6.5 for typical communication PCBs of analog and digital designs. The ranges are based on querying four different PCB manufacturers. The NRE expenses are based on the tooling necessary for making stencils for applying the circuit images on the PCBs and the test setup. Test costs are based on several iterations (revisions) of the PCB design.