Form Four

Product Information

Form Four Control Center

The Digitize Form Four is a power regulator that provides power, supervision and control for 100 mA telegraph boxes. The Form Four prevents excessive generation of heat which could damage circuitry and reduce the life of the equipment. The Card Cage provides the housing for one common card, and up to 10 Box or Alarm cards in any combination.

The Form Four Box Card supplies supervisory and control logic for repeating alarms to bell or recording circuits. It also automatically provides ground return capability for the reception of alarms from “Three Fold” type fire alarm boxes in the in the event of an open circuit.

The Alarm Card powers and supervises box circuits. A Common Card monitors the operation of the system. All abnormal conditions are indicated via visual and audible alarms. Power breaks, a missing card, and low or high line current are examples of situations that will activate the audible alarm. This card also has the ability to supervise the AC input of an external battery charger eliminator as well as the DC output from the battery.

The switching power supply enables the Form Four to convert the station power source to the required operating voltage efficiently. The Form Four operates from a 24-Volt DC power source.

A digital LED meter, mounted to the front panel, provides accurate voltage and current measurements on the line circuits. Voltage from line-to-ground and line-to-line can also be measured. The meter is common to all line circuits through push buttons and has a battery backup.

Each Box or Alarm card continuously monitors for proper line current. Under normal conditions, all box alarms are received from closed series circuits. Short circuit protection by switching power supply is used in all box and alarm circuits as well as automatic or manual line current regulation (switch selectable). If a break occurs in a box circuit, automatic conditioning to ground return mode is provided (on Box card only).

Modular Box and Alarm cards are programmable (via programming plug) for Type A, Type B or Type A/B operation. For Type B cards, fire alarm codes from a box circuit are automatically and simultaneously repeated into the other box and alarm circuits.