<Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (December 2010) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (December 2010) (Learn how and when to remove this template message) </Td> </Tr> <P> A fire alarm control panel (FACP), fire alarm control unit (FACU), or simply fire alarm panel is the controlling component of a fire alarm system . The panel receives information from devices designed to detect and report fires, monitors their operational integrity and provides for automatic control of equipment, and transmission of information necessary to prepare the facility for fire based on a predetermined sequence . The panel may also supply electrical energy to operate any associated initiating device, notification appliance, control, transmitter, or relay . There are four basic types of panels: coded panels, conventional panels, addressable panels, and multiplex systems . </P> <P> Coded panels were the earliest type of central fire alarm control, and were made during the 1800s to the 1970s . A coded panel is similar in many ways to a modern conventional panel (described below), except each zone was connected to its own code wheel (i.e. An alarm in zone 1 would sound code 1 - 2 - 4 (through the bells or horns in the building), while zone 2 would sound 1 - 2 - 5), which, depending on the way the panel was set up, would either do sets of four rounds of code until the initiating pull station was reset (similar to a coded pull station) or run continuously until the panel itself was reset . Large panels could take up an entire wall in a mechanical room, with dozens of code wheels . Lists of codes had to be maintained, sometimes with copies posted above pull stations (this setup is commonly seen in older wings of hospitals). Smaller panels could be set up in one of two ways . Most of the time, the panel would only have one zone, and therefore, only one code . Common one - zone codes were 4 - 4 - 0 and 17 - 0 - 0 (which is similar to the 120 bpm March Time setting used on later panels, which has in turn been replaced with an interrupted four count uniform temporal code 3 pattern used since 1996). Alternatively, the panel could be made with no code wheels, using only what was called the gong relay . Normally, this would be used in a system with coded pull stations to re-transmit the coding strikes from the pulls . However, it could also be used as its own zone, with the connected horns or bells sounding continuously instead of in a particular code . These panels are not common today, but can sometimes be found in older buildings such as those on college campuses or hospitals . </P>

What is the use of interface unit in fire alarm system
find me the text answering this question