THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
NATURE OF THE INVENTION

WEB ENABLED DATA CONCENTRATOR FOR REAL TIME UNITS COMMUNICABLE OVER RS485-STD MODBUS
PROTOCOL
A) TECHNICAL FIELD
The present invention relates generally to the field of data communication. In particular it relates to the field of data communication using a data conccnu a i < >r to enable configuration and management of multiple RTUs (Real Time lints; remotely either through Ethernet or modem connection.
B) BACKGROUND AND PRIOR ART
Data communication has been an important field since the inception of computer. In the present day scenario, data communication happens in various industries that use computers. For example, in small firms data communication happens through LAN (Local Area Network) and in medium and large sized firms data communication happens through WAN (Wide Area Network), which is a collection of two or more LANs. With the rapid growth in ilie* software and other related industries the proper connectivity or networking of all the terminals or devices and the proper transfer of data between eaeh ot them has become a major issue. Many networking protocols have- been designed to ensure a robust and reliable connection, like Ethernet, SKMP (Simple Network Management Protocol), etc. The networks within organizations have now grown out of proportions, which has led to the

discovery of devices that can manage and supervise the transfer of data through networks.
In US patent application bearing number 5982775, a simple method (<>i forwarding of multicast data frames over an Ethernet bridge has In en described. In this method a bridge forwarding multicast table, which commit the multicast destination address, is polled through a router. This multicast data frame is received by the bridge and the forwarding address is searched and according to it, it is forwarded to each port of the bridge which has subscribed for that particular multicast session, represented by the multicast destination address passed by the host.
In US patent application bearing number 5319754, a method of transfer of data between a computer and a host adapter using multiple arrays is described. The host computer has a system bus for communication between the host computer and the TTY or TTY and the host computer. The system bus has been allotted a memory for storing data. The data stored in the system bu:> includes a data buffer, which is used for the purpose of storing the data seni from the host computer to the TTY devices or from TTY devices to the host computer. There is also a content array, which is a collection of pointers terminated by a null pointer. Each of the pointers is pointing to a device identification handle and each consecutive pointer is pointing to the buffer data. It is also maintaining a count on the number of bytes of the have been allotted memory. There are receiving and transmitting arrays which are used to store the device identification handle and a count which tells about the size of data that can be transferred. There is a host adapter, which is used to update the pointer, which tells about the corresponding memory left in each ot the devices. It also transmits the data from computer to the TTY devices or TTY devices to the host computer. Some of these adapters are connected to lu<>h speed serial links for communication with a data link. The adapter automatic alb

detects the presence of a concentrator and switches to a high-speed link. Kach concentrator consists of many serial ports to connect to TTY devices and a high-speed link to connect to adapter's high-speed link. The data from tlie* several TTY's is send to the adapter data buffer where it is stored either on a configurable time basis or until a certain amount of data is present, after whicli the adapter interrupts the computer and transfers the data in one operation. Likewise, from the computer to the TTY devices, the data is stored and transferred to the adapter in one transfer operation.
The communication between the adapter and the concentrator through a lm>h speed serial communication link is achieved through a small fixed sized address packet, which serves as a high speed, low overhead address protocol. Kach high-speed link between an adaptor and a concentrator is achieved by a flow control of data. The concentrator follows a fail-safe global flow to prevent overflow of data.
In US patent application bearing number 5280586, a method of extendable data communication is shown using data concentrator. The system basically consists of a host computer, a plurality of I/O devices, a data concentrator, a system bus and a memory connected to that system bus. There is a communication link for sending and receiving data, which uses a pre-determined number o! data packets. It also contains a field for the type of packet and if the packet is data type it contains an address field, which contains a device communication port number, and the data that was sent to the communication port which is connected to any one of the I/O devices. The processor is basically used tot connecting to the host computer and receiving data from it and then transmitting it to the various I/O ports. Each concentrator consists of main serial ports to connect to I/O devices and a high-speed link to connect 10 adapter's high-speed link. The data from the several I/O devices is send to the adapter data buffer where it is stored either on a configurable time basis or tin til

a certain amount of data is present, after which the adapter interrupts the computer and transfers the data in one operation. Likewise, from the computer to the I/O devices, the data is stored and transferred to the adapter in one transfer operation. The communication between the adapter and the concentrator through a high-speed serial communication link is achieved through a small fixed sized address packet, which serves as a high speed, low-overhead address protocol. Each high-speed link between an adaptor ami a concentrator is achieved by a flow control of data. The concentrator follows a fail-safe global flow to prevent overflow of data.
In US patent bearing number 5226040, a method of data concentration for configuration of multiple TTY devices is shown. The system consists of a host computer, a system bus and many TTY devices. There is a system bus lor storing the data before sending .The system also consists of device driver whieh sends device identification handle, each one of which corresponds to a particular TTY device. There is a data concentrator used to manage the flow of data control. The data concentrator consists of several device ports. Also it contains a communication port for receiving data of pre-determined fixed size. It also contains a The main processing is receiving data through communication port and then transferring it to any one of the TTY communication port, through said port number in said address field according to the configuration field. The host computer has one or more adapters connected to it for transferring data to the several TTY devices. Some of these adapters are connected to high-speed serial links for communication with a data link. The adapter automatically detects the presence of a concentrator and switches to a high-speed link. This host adapter consist of a system bus which is used for receiving device identification handles from the host computer and converting it into a port number , and also receive host configuration command and to convert this command to packet configuration command . It further assembles a configuration packet and places port address in the address field.

Each concentrator consists of many serial ports to connect to TTY devices and a high-speed link to connect to adapter's high-speed link. The data from the several TTY's is send to the adapter data buffer where it is stored either on a configurable time basis or until a certain amount of data is present, after which the adapter interrupts the computer and transfers the data in one operaiion. likewise, from the computer to the TTY devices, the data is stored and transferred to the adapter in one transfer operation. The communication between the adapter and the concentrator through a high-speed serial communication link is achieved through a small fixed sized address packet, which serves as a high speed, low overhead address protocol. Each high-speed link between an adaptor and a concentrator is achieved by a flow control of data. The concentrator follows a fail-safe global flow to prevent overflow <>l data.
In US patent bearing number 4970718, an apparatus has been described which supplies channel control signal and maintenance signal in a serial data concentrator system. In this there is a data link (1000), which operates a I a renumber of concurrently working channels on a single pair of fiber optics, cable (10 and 1010). There is a receiver (1004A) on one end, which determines whether the signal being received is in synchronism with the signals which it receives over one of the cable (1010), and a transmitter to send an information along with the data to be send, to the device on the other end, to log off if it is not in synchronism at the other end. The transmitter further sends an error count at the other end, and responses to mode signal from the other end to reduce its signal power, which is used by maintenance personnel to perform many tests and procedures from a single end of the link .A single integrated circuit receives chip (1005A) receives data serially from a modularly expanded shift register in parallel and the chip sends the data in a serial reverse order.

In US patent bearing number 4726017, a multidrop data concentrator lot communication in a master-slave model has been designed. It uses a muluport multiplexer at the master site and at the slave sites, to interface multiple- pons to a single telephone communication link .At the master side .At the master side different type of data or signal processing equipments are joined to respective ports of a master communication multiplexer or concentrator. The input port of this master concentrator establishes a link through modem with each corresponding remote concentrator, which is coupled with a respective drop distributed data concentrator along the telephone link. The polling frames, which are assembled by the master concentrator, are sending in between the respective data packets that are send for the remote concentrators, li sequentially and periodically polls each respective port of all rei 1 n >t c concentrators for reply message to be transmitted to master site that has earlier requested for data.
. In the US patent numbered 3681755, a computer independent data concentrator has been described. In this, there is a remote system like a digital signal processing unit, which is used to interconnect multiple users over a single data line (like telephone line) without any changes in the data processing unit