In a connector, a first housing is provided with a projection, and a second housing is provided with a retainer engaged with the projection. The ring backs are selected by the called party and can be delivered to the calling party in many ways, such as by delivering a file, a pointer, or a command. In an embodiment, the basing pointer is determined to be uninitialized, and thus needs monitoring for initialization, by detecting an error that results from adding an offset for the variable to the contents of the basing pointer, or by detecting an error when the result of the adding is used as a pointer. A locate and isolate mode are provided, as well as multiple song selection, for choice of alternative songs played by the detector when the tone packets are detected. The processor may be configured to compare the aircraft position to the contents of a database, determine, based on the comparison, whether the aircraft is on a departure runway from which the aircraft is to depart, and generate an alarm if the aircraft is on the departure runway and the current control-surface configuration is different from the desired control-surface takeoff configuration.