Patent ID: 9462401
Filing Date: 2016-10-04
CPC Classification: H04R

Claim Text:
1. A method of operating a public address system having a plurality of loudspeakers, the method comprising: providing control circuitry; coupling each of the plurality of loudspeakers to the control circuitry via a two-wire loop that includes isolator modules; determining values of an impedance of the two-wire loop successively from isolator module to isolator module by successively connecting each respective isolator module of the plurality of loudspeakers to the two-wire loop proceeding from a start to an end of the two-wire loop while repeating an impedance measurement from the start of the two-wire loop after each successive connection; determining a value of an impedance of the entire two-wire loop; storing at least some of the determined values of the impedance of the two-wire loop successively from isolator module to isolator module and the determined value of the impedance of the entire two-wire loop as target values; intermittently determining the value of the impedance of the entire two-wire loop during operation; and determining if a variance exists between the determined value of the impedance of the entire two-wire loop during operation and the stored target values, and, responsive thereto, generating a fault message including a fault location.