Before any network upgrades are performed, PMD should be tested to see what the physical limitations are. The CMA5000a PMD (Polarization Mode Dispersion) module is designed to assess the capability of each fiber in the network and verify which transmission rates any given fiber can support. The CMA5000a PMD module can also identify fibers that are capable of the highest transmission rates, allowing service providers to assign these to key customers or the most demanding communications.