Alternatively, the system designer can specify a different bill of materials (BOM) for each data rate, creating a unique board type for each case. While this approach does not incur the board area penalty, as does the above parallel architecture, it does not allow for software provisioning of the service in the field and it increases the number of board types that must be kept in inventory. Also, neither approach provides any enhancement to the board test capability. System level timing architectures such as these have not changed much over time because of the lack of viable alternative technologies. The architectures have the appearance of being stopgap measures until more efficient solutions are found.