Overhead Travel Information System

The Overhead Travel Information System (OTIS) provides vehicle operator with supplementary information on a Vacuum Fluorescent (VF) display. The OTIS is located in overhead console. Vehicle operator selects and resets display functions through the use of 4 buttons (US/M, STEP, C/T and RESET). The OTIS obtains most of its information over the Programmable Communication Interface (PCI) multiplex system (bus).

The OTIS powers up when it senses battery voltage on the ignition switch input circuit. The OTIS blanks the display, then illuminates all segments of the VF display. During this time, the OTIS sends and receives information over the PCI bus to determine what to display after its 2-second initialization period. OTIS will display dashes (- - -) for any of the screens for which it did not receive PCI bus messages during the 2-second initialization period. Dashes will be replaced by valid information if and when it is received.