Diagnosis Codes - click to display a list of all diagnosis codes in the system. From the Diagnosis Codes list you can add, edit and print your current list of diagnosis codes.  Service Codes - click to display a list of all service codes in your system. From the Service Codes List you can add, edit and print your current list of service codes. Place of Service Codes - click to display a list of all "place of service" codes in your system (i.e. 11-office, 12-home etc.). From this list you can add, edit and print your current list of service places. Modifier Codes - click to display a list of all service modifier codes in your system.