Utilizing existing wiring can reduce the high cost of new or retrofit emergency voice communication systems. The Bank of Boston-now Fleet-had to upgrade an existing system that had a mix of 25- and 70-volt speakers on different floors. By using an audio control on each floor, the riser and the speaker wiring on each floor did not need replacement. Also, using distributed controls, the speaker voltage on each floor could be set independent of the audio output from the central control.
Applied American Technologies.