The Model 902 Priority Paging Switcher Card is designed for use in professional audio applications. Each unit features six (6) paging inputs, one (1) line level output, and a switch closure circuit for control of priority bypass relays, or other paging functions. Typical applications are public address systems in buildings such as airports, factories, hospitals, courthouses, casinos, convention centers, libraries, hotels, racetracks, and office buildings. The mechanical construction of the Model 902 allows mounting of up to ten (10) units in a Model 857B Card Frame, or nine (9) units in a Model 858B Card Frame. Each Model 902 card unplugs from the front of the card frame, without the need for removing any wires from the rear of the card frame. Spare units may be placed into service in a matter of minutes. Each Model 902 has six inputs, which are arranged in a series configuration. Each input passes thru a number of double-pole double-throw relays. Activating any higher priority relay disconnects the relay chain at the selected point, and allows the higher priority input channel to pass thru to the output stage. Input stage number 6 is normally used for background music, and is configured in the normally ON position. Activating any of the other five (5) inputs will disconnect input number 6. The Model 902 Priority Paging Switcher Card is balanced in both the input and output stages. The output level may be adjusted by using the on-board output level control trimpot.