BT2-3 Building Transceiver The BT2-3 Building Transceiver provides FCC Certified narrowband radio signaling of alarm and trouble conditions from local fire alarm systems to Monaco's central D-500 Radio Alarm System. Local control panels or supervisory devices that have isolated dry contacts which provide a short for an alarm condition and an open for a trouble condition may be connected directly to the BT2 zone inputs. Interfacing relays may be used to connect other types of outputs. The BT2-3 initiates a report to the D-500 whenever a zone alarm or trouble or BT2 trouble is detected. It transmits DTMF encoded FM signals which identify the condition and zone or BT2 number. An alarm is transmitted three times and a trouble is transmitted twice. When the zone input is returned to normal, the BT2-3 sends an end alarm or end trouble message. The D-500 supervises the radio link with a system interrogation sent automatically at intervals of one to 24 hours as programmed by the user. All or individual BT2s may be interrogated manually at any other time. The BT2 reply identifies any off-normal conditions that exist: BT2 ac fail, battery fault or tamper and/or a zone alarm or trouble. Provides DTMF encoded FCC Certified narrowband radio transmission of alarms, troubles and restorations for up to five zones Communication with the D-500 Plus is supervised by scheduled and manual interrogations A zone input delay of 2 or 15 seconds may be selected for the BT2 Zone identification and BT2 numbers are entered by the user on DIP switches Low battery, ac fail and tamper (optional) conditions are reported with the BT2 number; ac fail reporting may be inhibited LEDs identify BT2 and zone status Carrier detect identifies possible transmission interference; variable delay routine prevents simultaneous transmissions from several BT2s Provides 60-hour battery backup and charging circuitry 4 watts RF output power (Selected frequencies available with 2 watts RF output power)