Systems and methods for implementing coexistence by requesting access to a channel in power line communications are described. For a data object definition in an XML schema, a user interface object may be defined, and a memory store for the data object may be created and bound to the user interface object. The current monitor measures current drawn by the passenger bridge and the battery charger to provide a signal to the controller indicative of the power consumption of the passenger bridge and the battery charger. The time slot allocating unit comprises a plurality of slot tables with a plurality of entries. A graphical definition of the Web service is stored in the system data store.