DESC:Field of the invention:

The present invention relates to public address systems and more particularly relates to a public address systemhaving aprogrammble logic controller (PLC) for implementing intelligent features with pre-timed recorded messages, an electronic private branch exchange (EPBX) interface and priorities for zonal announcements.

Background of the invention:

Normally, in a public address system; one is able to make announcements from an announcement desk on zonal basis and also initiate alarms. Some systems also provide an electronic private branch exchange (EPBX) connectivity using special hardware in the EPBX exchange. Some systems also provide recorded messages in place of alarms. These systems normally work with a central controller based on dedicated hardware platform using proprietary software.

Presently separate electronic hardware is needed for each type of function or requires special software development on a dedicated hardware platform. Referring to Figure 1, ablock diagram of an existing public address system (10), in accordance with a prior art is shown. The existing public address system consists of separate hardware blocks like, audio signal conditioning module, EPBX coupler module and specifically developed digital controller hardware with dedicated software, among others. The changes needed by users, such as, time of relaying recorded messages, type of priority etc. require changes in proprietary software. This may not be possible in the field.

Accordingly, there exists a need of public address system with programmble logic controller that overcomes the above mentioned drawbacks in the prior art.
Objects of the invention:

An object of the present invention is to reduce the time and development efforts required for implementation of any special functions in a public address system, such as, zonal announcements, priority handling, alarm generation, interface with other systems like EPBX, fire alarm and relaying timed recorded messages.

An object of the present invention is to provide pre-timed relay of pre-recorded messages, that are helpful in compliance of safety or health related procedures.

Summary of the invention:

The present invention relates to public address systems and more particularly relates to a public address system and method thereof, having a programmble logic controller (PLC) for implementing intelligent features with pre-timed recorded messages, an electronic private branch exchange (EPBX) interface and priorities for zonal announcements.

According to one of the embodiments of the present invention a public addressing system comprise of programmable logic controller (PLC) module,an audio signal processing unit,at least one announcement unit,electronic private branch exchange (EPBX), a zone relay matrix,at least one loud speaker,at least one amplifier,at least one loudspeaker cable,a plurality of signal cables, at least one mains cable,one EPBX subscriber line. According to one of the embodiments of the present invention,the programmable logic controller (PLC) module is configured to execute a plurality of real time functions. The audio signal processing unit is configured to receive audio signals as inputs from announcement desks and EPBX subscriber line and process them based on the control signal received from the PLC. The announcement unit is electrically and communicatively coupled to the programmable logic controller (PLC) module and to the audio signal processing unit. The electronic private branch exchange (EPBX) is configured to provide communication interface for receiving calls from external world and provide a plurality of speech signal, a plurality of pulse-tones in the form of various pulses. The zone relay matrix is configured toconnect audio signals and alarms to amplifiers assigned for zones, based on a plurality of control signals received from programmable logic controller (PLC) module. The amplifier is configured to amplify selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to loud speaker to relay it in at least one determined zone. The loud speaker is configured to relay selected audio signals and alarms to determined zone. The loud speaker is configured to relay selected audio signals and alarms to determined zone. The plurality of signal cables,are configured to couple a plurality of modules constituting the system. The loudspeaker cable is configured to couple the amplifier assigned for a zone to zone loudspeaker. The mains cable is configured to power the plurality of modules constituting the system. The EPBX subscriber line is configured to provide speech signal, pulses related to various tones from the EPBX.

According to one of the embodiments of the present inventiona method for public addressing system, includes electronic private branch exchange (EPBX) communication to provide interface for receiving calls from external world and providing a speech signal, a plurality of pulse-tones in the form of various pulses. The method includes providing an EPBX subscriber line from the EPBX. The method includes receiving by audio signal processing unit, the audio signals from at least one announcement desk and speech signal from the EPBX subscriber line. The method includes receiving by programmable logic controller (PLC) module, at least on zone selection input from at least one zone selection switch from an announcement desk and at least ‘Press to Talk’ switch and a plurality of pulses related to various tones from the EPBX subscriber line. The method includes executing, by programmable logic controller (PLC) module a plurality of real time function. The method includes providing by at least one real time clock timing control signals to synchronize time based functioning of the plurality of modules constituting the system, for initiating timed announcements/alarms. The method includes processing by an audio signal processing unit audio signals and digital signals received as inputs based on the control signal received from the PLC. The method includes electrically and communicatively coupling at least one announcement unit to the programmable logic controller (PLC) module and to the audio signal processing unit. The method further includes relaying by zone relay matrix audio signals and alarms to determined zone/s based on a plurality of control signals received from programmable logic controller (PLC) module. The method includes communicatively coupling by loudspeaker cable, at least one amplifier to at least one loudspeaker. The method includes amplifying by at least one amplifier selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to the at least one loud speaker to relay it in at least one determined zone. The method includes relaying by at least one loud speaker selected audio signals and alarms to at least one determined zone. The method consecutively includes powering by at least one mains cable, the plurality of modules constituting the system.

Brief description of the drawings:

The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein

Figure 1 shows a block diagram of an existing public address system, in accordance with a prior art; and

Figure 2 shows a a block diagram of a public address systemwith a programmble logic controller (PLC), in accordance with the present invention.

Detailed description of the invention:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention is a public address system and method thereof having a programmble logic controller (PLC) for implementing intelligent features with pre-timed recorded messages, an electronic private branch exchange (EPBX) interface and priorities for zonal announcements.

In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.

The various embodiments of the present invention provide a system and method thereof for a public address system having a programmble logic controller (PLC) for implementing intelligent features with pre-timed recorded messages, an electronic private branch exchange (EPBX) interface and priorities for zonal announcements.

Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
The systems/device and methods described herein are explained using examples with specific details for better understanding. However, the disclosed embodiments can be worked on by a person skilled in the art without the use of these specific details.

Throughout this application, with respect to all reasonable derivatives of such terms, and unless otherwise specified (and/or unless the particular context clearly dictates otherwise), each usage of:
“a” or “an” is meant to read as “at least one.”
“the” is meant to be read as “the at least one.”
References in the present invention to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

Embodiments of the present invention include various steps, which will be described below. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special purpose processor programmed with the instructions to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, firmware and/or by human operators.

In some embodiments, the systems may be configured as a distributed system where one or more components of the system are distributed across one or more networks in a cloud computing system.

If the specification states a component or feature "may' can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
As used in the description herein and throughout the claims that follow, the meaning of "a, an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this invention will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).

Hereinafter, embodiments will be described in detail. For clarity of the description, known constructions and functions will be omitted. Parts of the description may be presented in terms of operations performed by an Electrical/Electronic system, using terms such as state, link, ground, fault, packet and the like, consistent with the manner commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. As is well understood by those skilled in the art, these quantities take the form of data stored/transferred in the form of electrical, magnetic, or optical signals capable of being stored, transferred, combined, and otherwise manipulated through mechanical and electrical components of the electronic/electrical systems; and the term electronic/electrical/computer system includes general purpose as well as special purpose data processing machines, switches, and the like, that are standalone, adjunct or embedded.
While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description as well as in a table below.

Component No Component name
100 Public address system
20 Subscriber line from EPBX
25 Audio signal processing unit
30 Programmble logic controller (PLC)
40 Announcement units

Referring to Figure 2, a perspective view of a public address system (100) (herinafter referred as, “the system (100)”) with a programmble logic controller (PLC), in accordance with the present invention is shown. The system (100) comprises signal cables (not numbered), loudspeaker cables (not numbered), a mains cable (not numbered), a subscriber line (20) from an electronic private branch exchange (EPBX), a programmble logic controller (PLC) (30) with an audio signal processing unit (25), announcement units (40) ans a loud speaker (not shown) that are operably conncted with each other.The announcement units (40) are connected to the programmble logic controller (PLC) (30) and audio signal processing unit(25).

The system (100)usescontrolling power of the programmble logic controller (PLC) (30) that have real time functions. The PLC (30) controls various functions including selecting zones, selecting priorities between various announcement points, selection of particular alarm or recorded message, relaying selected message at pre-programmed time of the day, detecting the calls and termination of calls, from the standard EPBX subscriber line (20), interfacing with other systems like fire alarm system, access control and intrusion alarm system, for relaying alarms in to designated zones, handling of audio signals for announcement, alarm, EPBX speech, recoded audio in the audio signal processing unit and like but not limited thereto.

The audio signal processing unit(25) receives audio signals from announcement units (40) andtheEPBX subscriber line (20) and processes them as governed by the PLC (30). Such processed signals are further fed to amplifiers (not shown) and relayed through loudspeakers.

In an operation, the PLC (30) has a central processing unit that controls other modules like digital input module, digital out modules and like. Using a standard human-machine interface (not shown), one can program the logic and timings for various operations.The press to talk switch (not shown) and zone selection switches (not shown) from an announcement desk, potential free contacts (not shown) from fire alarm or other systems are connected to the PLC (30) as digital input signals.Thelogic program in the PLC (30) determines selection of zones, priorities and accordingly digital outputs of the PLC (30) are used to route the audio signals to required zones.Real time clock available in the PLC (30) is used for initiating timed announcements/ alarms. Some digital outputs are used for selecting particular alarm or recorded message residing on the audio signal processing unit.The audio signal (EPBX) subscriber line (20) is processed in the audio signal processing unit to separate the speech signal and pulses related to various tones from the EPBX. The pulses are fed to the PLC (30) as digital inputs. In an embodiment, the PLC inputs are programmed to detect the ‘Dial tone’, ‘Ring tone’ and ‘Engage tone’ from these pulses and accordingly to accept or terminate a call.

In an implementation according to one of the embodiment of the present invention a public addressing system comprise of at least one programmable logic controller (PLC) module,an audio signal processing unit,at least one announcement unit,at least one electronic private branch exchange (EPBX),at least one zone relay matrix,at least one loud speaker,at least one amplifier,at least one loudspeaker cable,a plurality of signal cables, at least one main cable,at least one EPBX subscriber line.

In one of the implementation according to one of the embodiments of the present invention the at least one programmable logic controller (PLC) module is configured to execute a plurality of real time function. The audio signal processing unit is configured to receive audio signals as inputs and process them based on the control signal received from the PLC. The at least one announcement unit electrically and communicatively coupled to the at least one programmable logic controller (PLC) module and to the audio signal processing unit. The at least one electronic private branch exchange (EPBX) is configured to provide communication interface for receiving calls from external world and provide a plurality of speech signal, a plurality of pulses tones in the form of various pulses. The at least one zone relay matrix is configured to relay audio signals and alarms to determined zones based on a plurality of control signals received from at least one programmable logic controller (PLC) module. The at least one loud speaker is configured to relay selected audio signals and alarms to at least one determined zone. The at least one amplifier is configured to amplify selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to the at least one loud speaker to relay it in at least one determined zone. The plurality of signal cables is configured to communicatively couple a plurality of modules constituting the system. The at least one loudspeaker cable is configured to communicatively couple the at least one amplifier to the at least one loudspeaker. The at least one main cable is configured to power the plurality of modules constituting the system. The at least one EPBX subscriber line is configured to provide speech signal, pulses related to various tones from the EPBX.

In one of the implementation according to one of the embodiments of the present invention the at least one programmable logic controller (PLC) module comprise of at least one central processing unit,at least one digital input module,at least one digital out module,at least one human-machine interface, and at least one real time clock. The at least one central processing unit is configured to control a plurality of modules constituting the at least one programmable logic controller (PLC) module. The at least one digital input module is configured to receive a plurality of digital inputs from a plurality of modules constituting the system and a plurality of peripheral devices. The at least one digital out module is configured to provide digital output signal generated by logic program of the at least one programmable logic controller (PLC) module. The at least one human-machine interface is configured to facilitate programing logic and timings for various operation. The at least one real time clock is configured to provide timing control signals to synchronize time based functioning of the plurality of modules constituting the system.

In one of the implementation according to one of the embodiments of the present invention the at least one central processing unit of the at least one programmable logic controller through controlling power configured to perform a plurality of real time functions including receiving inputs from at least one zone selection switch of announcement desk, selecting zones, selecting priorities between various announcement points, selection of particular alarm or recorded message, relaying selected message at pre-programmed time of the day, detecting the calls and termination of calls from the standard EPBX subscriber line, interfacing with other systems like fire alarm system, access control and intrusion alarm system for relaying alarms in to designated zones, handling of audio signals for announcement, alarm, EPBX speech, and recoded audio in the audio signal processing unit and providing a plurality of control signals to the at least one zone relay matrix to relay audio signals and alarms to determined zones.

In one of the implementation according to one of the embodiments of the present invention the audio signal processing unit comprise of at least one processor, at least one alarm generator module, and at least one memory. The at least one processor is configured tocontrol the overall operations of the audio signal processing unit, receive audio signals as inputs from at least one announcement desk, and at least one EPBX subscriber line and process them based on the control signal received from the at least one programmable logic controller (PLC) module, generate a plurality of control signal based on the instruction received in the form of digital outputs of digital out module from the at least one programmable logic controller (PLC) module for selection of a particular alarm or a recorded message, receive at least one EPBX subscriber line audio signals, process at least one EPBX subscriber line audio signals to separate at least one speech signal and a plurality of pulses related to various tones from the EPBX, providing a plurality of pulses related to various tones from the EPBX separated from at least one EPBX subscriber line audio signals as digital inputs to at least one programmable logic controller (PLC). The at least one alarm generator module is configured to generate alarm based on the selection control signal received from the at least one processor of the audio signal processing unit. The at least one memory is communicatively coupled to at least one programmable logic controller (PLC) module and configured to store a plurality of recorded messages.

In one of the implementation according to one of the embodiments of the present inventiontheaudio signal processing unit is configured to receive audio signals from announcement units and the EPBX subscriber line, process the receive audio signals from announcement units and the EPBX subscriber line based on the control signal received from the at least one programmable logic controller (PLC) module, feed the processed signals to amplifiers to relay them through loudspeakers.

In one of the implementation according to one of the embodiments of the present invention the at least one digital input module of the at least one programmable logic controller (PLC) module is configured to detect the ‘Dial tone’, ‘Ring tone’ and ‘Engage tone’ from the digital inputs of pulses related to various tones separated from at least one EPBX subscriber line audio signals received from audio signal processing unit and accordingly accept or terminate a call.

In one of the implementation according to one of the embodiments of the present invention the at least one digital input module of the at least one programmable logic controller (PLC) module is configured to receive digital inputs from a plurality of modules constituting the system and a plurality of peripheral devices including at least one press to talk switch, at least one zone selection switch from an announcement desk, potential free contacts from fire alarm or other systems

In one of the implementation according to one of the embodiments of the present invention the at least one digital out module of the at least one programmable logic controller (PLC) module is configured to provide digital output signals corresponding to the selection of zones and priorities determined by logic program of the at least one programmable logic controller (PLC) module.

In one of the implementation according to one of the embodiments of the present invention the at least one digital out module of the at least one programmable logic controller (PLC) module is configured to provide digital output signals corresponding to the selection of zones and priorities determined by logic program of the at least one programmable logic controller (PLC) module to route the audio signals to required zones.

In one of the implementation according to one of the embodiments of the present invention the at least one real time clock of the at least one programmable logic controller (PLC) module is configured to provide timing control signals to synchronize time based functioning of the plurality of modules constituting the system for initiating timed announcements/alarms.

In one of the implementation according to one of the embodiments of the present inventiona method for public addressing system includes providing by at least one electronic private branch exchange (EPBX) communication interface for receiving calls from external world and providing a plurality of speech signal, a plurality of pulses tones in the form of various pulses. The method includes providing by at least one EPBX subscriber line speech signal, pulses related to various tones from the EPBX. The method includes receiving by an audio signal processing unit audio signals from at least one press to talk switch of an announcement desk and at least one speech signal and a plurality of pulses related to various tones from the EPBX subscriber line. The method includes receiving by at least one programmable logic controller (PLC) module at least on zone selection input from at least one zone selection switch from an announcement desk and at least one speech signal and a plurality of pulses related to various tones from the EPBX subscriber line. The method includes executing, by at least one programmable logic controller (PLC) module a plurality of real time function. The method includes providing by at least one real time clock timing control signals to synchronize time based functioning of the plurality of modules constituting the system for initiating timed announcements/alarms. The method includes processing by an audio signal processing unit audio signals and digital signals received as inputs based on the control signal received from the PLC. The method includes electrically and communicatively coupling at least one announcement unit to the at least one programmable logic controller (PLC) module and to the audio signal processing unit. The method further includes relaying by at least one zone relay matrix audio signals and alarms to determined zones based on a plurality of control signals received from at least one programmable logic controller (PLC) module. The method includes communicatively coupling by at least one loudspeaker cable at least one amplifier to at least one loudspeaker. The method includes amplifying by at least one amplifier selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to the at least one loud speaker to relay it in at least one determined zone. The method includes relaying by at least one loud speaker selected audio signals and alarms to at least one determined zone. The method includes communicatively coupling by a plurality of signal cables a plurality of modules constituting the system. The method consecutively includes powering by at least one main cable the plurality of modules constituting the system.

In one of the implementation according to one of the embodiments of the present inventionthe method of executing, by at least one programmable logic controller (PLC) module a plurality of real time function includes receiving inputs from at least one zone selection switch of announcement desk. The method includes selecting zones. The method includes selecting priorities between various announcement points. The method includes selecting particular alarm or recorded message. The method includes relaying selected message at pre-programmed time of the day. The method includes detecting the calls and termination of calls from the standard EPBX subscriber line. The method includes interfacing with other systems like fire alarm system, access control and intrusion alarm system for relaying alarms in to designated zones. The method includes handling audio signals for announcement, alarm, EPBX speech, and recoded audio in the audio signal processing unit. The method further includes providing a plurality of control signals to the at least one zone relay matrix to relay audio signals and alarms to determined zones.

Advantages of the invention:

1. Using this method, Standard hardware can handle most of the requirements of announcement systems. Based on a set of requirements, it can be made in to a standard product.
2. User defined facilities; timing instances can be programmed using open sourced application software provided by the PLC vendors.
3. Reduced hardware modules in the controller and consequently reduced internal wiring.
4. Reduced Product Development costs.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention asdescribed above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the scope of the invention. ,CLAIMS:WE CLAIM:
1. A system for public addressing, the public addressing system comprises:
one programmable logic controller (PLC) module, the programmable logic controller (PLC) module is configured to execute a plurality of real time function;
an audio signal processing unit, the audio signal processing unit configured to receive audio signals as inputs and process them based on the control signal received from the PLC ;
at least one announcement unit, the announcement unit electrically and communicatively coupled to the programmable logic controller (PLC) module and to the audio signal processing unit;
a electronic private branch exchange (EPBX), the e electronic private branch exchange (EPBX) configured to provide communication interface for receiving calls from external world and provide a plurality of speech signal, a plurality of pulse-tones in the form of subscriber lines;
one zone relay matrix, the zone relay matrix configured to relay audio signals and alarms to determined zones based on a plurality of control signals received from programmable logic controller (PLC) module;
at least one loud speaker, the one loud speaker configured to relay selected audio signals and alarms to at least one determined zone;
at least one amplifier, the amplifier configured to amplify selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to the loud speaker to relay it in at least one determined zone;
a plurality of signal cables, the plurality of signal cables configured to communicatively couple a plurality of modules constituting the system;
at least one loudspeaker cable, the loudspeaker cable configured to couple the at least one amplifier to the loudspeaker/s;
at least one mains cable, the mains cable configured to power the plurality of modules constituting the system; and
one EPBX subscriber line, the EPBX subscriber line configured to provide speech signal and pulses related to various tones from the EPBX.

2. The system as claimed in claim 1 wherein the programmable logic controller (PLC) module comprises
a central processing unit, the central processing unit configured to control a plurality of modules constituting the programmable logic controller (PLC) module;
at least one digital input module, the digital input module configured to receive a plurality of digital inputs from a plurality of modules constituting the system and a plurality of peripheral devices;
at least one digital out module, the digital out module configured to provide digital output signal generated by logic program of the at least one programmable logic controller (PLC) module;
at least one human-machine interface, the human-machine interface configured to facilitate programing logic and timings for various operation;
at least one real time clock, the real time clock configured to provide timing control signals to synchronize time based functioning of the plurality of modules constituting the system;

3. The system as claimed in claim 1 wherein the central processing unit of the programmable logic controller configured to perform a plurality of real time functions including receiving inputs from at least one zone selection switch of announcement desk, selecting zones, selecting priorities between various announcement points, selection of particular alarm or recorded message, relaying selected message at pre-programmed time of the day, detecting the calls and termination of calls from the standard EPBX subscriber line, interfacing with other systems like fire alarm system, access control and intrusion alarm system for relaying alarms in to designated zones, handling of audio signals for announcement, alarm, EPBX speech, and recoded audio in the audio signal processing unit and providing a plurality of control signals to the at least one zone relay matrix to relay audio signals and alarms to determined zones.

4. The system as claimed in claim 1 wherein audio signal processing unit comprises
a processing unit configured to
control the overall operations of the audio signal processing unit;
receive audio signals as inputs from at least one announcement desk, and one EPBX subscriber line and process them to give uniform audio signal level, based on the control signals received from the programmable logic controller (PLC) module;
generate a plurality of alarm signals or recorded messages based on the instruction received in the form of digital outputs of digital output module from the programmable logic controller (PLC) module for selection of a particular alarm;
receive one EPBX subscriber line audio signals;
process EPBX subscriber line audio signals to separate speech signal and a plurality of pulses related to various tones from the EPBX;
providing such plurality of pulses related to various tones from the EPBX separated from EPBX subscriber line audio signals as digital inputs to programmable logic controller (PLC);
at least one memory, the at least one memory coupled to programmable logic controller (PLC) module and configured to store a plurality of recorded messages

5. The system as claimed in claim 1 wherein audio signal processing unit configured to
receive audio signals from announcement units and the EPBX subscriber line;
process the receive audio signals from announcement units and the EPBX subscriber line based on the control signal received from the programmable logic controller (PLC) module;
feed the processed signals to amplifiers to relay them through loudspeakers.

6. The system as claimed in claim 1 wherein the digital input module of the programmable logic controller (PLC) module is configured to detect the ‘Dial tone’, ‘Ring tone’ and ‘Engage tone’ from the digital inputs of pulses related to various tones separated from EPBX subscriber line audio signals received from audio signal processing unit and accordingly accept or terminate a call.

7. The system as claimed in claim 1 wherein the digital input module of the programmable logic controller (PLC) module is configured to receive digital inputs from a plurality of modules constituting the system and a plurality of peripheral devices including at least one press to talk switch, at least one zone selection switch from an announcement desk, potential free contacts from fire alarm or other systems

8. The system as claimed in claim 1 wherein the digital out module of the programmable logic controller (PLC) module is configured to provide digital output signals corresponding to the selection of zones and priorities determined by logic program of the programmable logic controller (PLC) module.

9. The system as claimed in claim 1 wherein the digital out module of the programmable logic controller (PLC) module is configured to provide digital output signals corresponding to the selection of zones and priorities determined by logic program of the programmable logic controller (PLC) module to route the audio signals to required zones.

10. The system as claimed in claim 1 wherein the real time clock of the programmable logic controller (PLC) module is configured to provide timing control signals to synchronize time based functioning of the plurality of modules constituting the system for initiating timed announcements/alarms.

11. A method for public addressing system, said method comprising steps of:
providing by electronic private branch exchange (EPBX) communication interface for receiving calls from external world and providing a plurality of speech signal, a plurality of pulses tones in the form of various pulses;
providing by EPBX subscriber line speech signal, pulses related to various tones from the EPBX.
receiving by an audio signal processing unit audio signals from press to talk switch of an announcement desk and speech signal and a plurality of pulses related to various tones from the EPBX subscriber line;
receiving by programmable logic controller (PLC) module at least on zone selection input from zone selection switch from an announcement desk and speech signal and a plurality of pulses related to various tones from the EPBX subscriber line;
executing, by programmable logic controller (PLC) module a plurality of real time function;
providing by real time clock timing control signals to synchronize time based functioning of the plurality of modules constituting the system for initiating timed announcements/alarms;
processing by an audio signal processing unit audio signals and digital signals received as inputs based on the control signal received from the PLC ;
electrically and communicatively coupling at least one announcement unit to the programmable logic controller (PLC) module and to the audio signal processing unit;
relaying by zone relay matrix audio signals and alarms to determined zones based on a plurality of control signals received from programmable logic controller (PLC) module;
communicatively coupling by loudspeaker cable amplifier to loudspeaker;
amplifying by amplifier selected audio signals and alarms to be relayed and provide amplified input of selected audio signals and alarms to the loud speaker to relay it in determined zone;
relaying by loud speaker selected audio signals and alarms to determined zone;
communicatively coupling by a plurality of signal cables a plurality of modules constituting the system; and
powering by main cable the plurality of modules constituting the system.

12. The method as claimed in claim 11 wherein step of executing, by programmable logic controller (PLC) module a plurality of real time function includes steps of
receiving inputs from at least one zone selection switch of announcement desk;
selecting zones;
selecting priorities between various announcement points;
selecting particular alarm or recorded message;
relaying selected message at pre-programmed time of the day;
detecting the calls and termination of calls from the standard EPBX subscriber line;
interfacing with other systems like fire alarm system, access control and intrusion alarm system for relaying alarms in to designated zones;
handling audio signals for announcement, alarm, EPBX speech, and recoded audio in the audio signal processing unit; and
providinga plurality of control signals to the zone relay matrix to relay audio signals and alarms to determined zones.

Dates this 15thday of January 2022

Prafulla Wange
Agent for the Applicant
IN/PA-2058