This is a project is designed to interface an existing wired alarm to a wireless alarm system. The circuit board should be single-sided surface mount technology and fit inside ZTX965D transmitter top cover and attach to a modified cable from the LP10 alarm controller of the ventilator.
DC power is supplied by the LP10 (+8 VDC) and regulated to +5 VDC which is the VCC for the ICs and power for the SSR (solid-state relay).
When there is a fault condition with the ventilator a logic low is sent to the inverting input on the comparator which drives the output low (or 0 VDC). This enables the SSR which passes a 'ground fault' on the input of the ZTX965D which sends the alarm condition to the base station receiver alerting staff as to the issue.