Alarm Annunciator

Type 8421 Alarm Annunciator

Type 8421



The type 8421 Alarm Annunciator is an integral part of the 8421 Universal display and Control (UDC) series of products designed specifically for the marine industry. It is a compact, modular solid state alarm annunciator for operation with digital (on-off) type sensors. Operating voltage is 12, 24 or 32 volts DC direct from ship's batteries. Special cables are not required.

Highly visible engraved LED type displays offer a large white engraving surface which becomes a brilliant red when turned on. LAMP type displays feature colored lenses in a compact high density format.

Up to four alarm points per module are provided using CMOS circuitry under microprocessor control. In a 19" high enclosure, up to 32 LED or 64 LAMP display alarm points are available. Dimming control is included as required.

All modules are plug-in and front removable without tools. Lenses and bulbs are front replaceable and an internal fuse is accessible on the control module. All PC boards are ultrasonically cleaned, conformal coated and system tested prior to shipment.


Remote fault contacts may be normally open (closed on fault) or normally closed (open on fault). Also, using an optional end of line resistor, open circuit, line shorts and status change can be detected. Each alarm is delayed by an adjustable time period of 0.5 to 60 seconds. Any alarm which persists longer than the set time delay is captured and will be held until acknowledged. Automatic reset occurs after the alarm has been acknowledged and corrected.

The front display will flash for each new fault until acknowledged and will remain on steady while the fault persists. Also, new faults operate an internal horn as well as external horn/beacon circuits. Horns will operate until acknowledged or silenced. However, if silenced first, the alarm display will continue to flash until it is acknowledged. When a new fault occurs the silence pushbutton flashes. This provides a quick visual indication of which enclosure is annunciating the alarm, in multiple enclosure installations.

A test pushbutton is provided which, while it is pressed, will insert a fictitious fault into the input of all circuits. Time delays are also checked by pushing the button for longer than the maximum delay. Testing may occur at any time without altering the status of existing alarm displays.

Field Programmable Features

Additional features which are included as standard, and which may be field programmed, include:

All field programming can be done at the rear terminals or by included jumpers and switches on each printed circuit board. A readily accessible fuse is provided in the control module. All PC boards are conformal coated and system tested before shipment.


Additional equipment is available to complete the alarm system including: remote group alarm repeaters, single point displays, cabin repeaters, watch keeping systems, cabin call systems, logic and control units, overload alarms, air horns, electric and electronic horns, rotating beacons, strobes, mimic displays, etc.

See Type 8421 UDC for display and control functions that are available in conjunction with alarm functions.

Typical Installations

Type 8421 Alarm Annunciator Panels are used on a variety of vessels from large freighters to private yachts.

TEL (604) 433-4644    FAX (604) 433-5570