Patent ID: 9741239
Date: 2017-08-22
CPC Classifications: G08B

Claim:
1. A monitoring system comprising: a single-mode wired control unit connected to a wire loop; and a multi-mode wired and wireless control unit that replaces the single-mode wired control unit by connecting the multi-mode wired and wireless control unit to the wire loop, wherein the multi-mode wired and wireless control unit determines an end-of-line resistance value of the wire loop to calibrate the multi-mode wired and wireless control unit to the wire loop, wherein the multi-mode wired and wireless control unit stores the end-of-line resistance value, wherein the multi-mode wired and wireless control unit includes an input-output port for communicating with the wire loop, wherein the multi-mode wired and wireless control unit stores a voltage value for the wire loop, wherein the multi-mode wired and wireless control unit compares the voltage value as stored to a current loop voltage value, and wherein the multi-mode wired and wireless control unit, responsive to results of comparing the voltage value as stored to the current loop voltage value, generates a trouble indicator when the current loop voltage value falls outside of a predetermined range indicative of acceptable operation.