Field of the Invention

In the present invention relates to the functionalities of a land line phone are increased to a higher level.

Background of the Invention

The existing product facilitates the text message transmission to a landline phone based upon the concept of CDMA (Code Division Multiplexing Access). In CDMA many codes occupy the same channel, but only users associated with a particular code can understand each other.

Objective of the Invention

In the present invention relates to transmit and receive text messages from a landline connected with the setup to another Corresponding landline phone and hardcore electronics and works on the aspects of decoding and serial communication.

Summary of the Invention

To send a text message, the desired location is first to be called. When the telephone "rings", there is a A.C voltage of 148 v in the line. The Diode (IN 4148) in the ring detector is reversing biased and conducts only during the negative cycle. The diode is connected to a opto coupler device. The photo transistor in the opto coupler conducts and the signals from the transmitter is fed into the timer(IC 555). The output of the timer is fed into the microcontroller. The pin 13 in the microcontroller which is initially in high state is now in state 0. That is, an interrupt is caused. During the positive cycle, the diode does not conduct and LED ceases to glow. The pin 13 is pulled back to state 1. The whole process is repeated for seven rings. The timer is used to feed the signal to the microcontroller for constant time period irrespective of length of the "rings". When the interrupt occurs for the SEVENTH time the relay circuit is activated. The relay circuit consists of a transistor based transformer and a hook switch. When the microcontroller activates the relay transistor, the transformer is activated and the switch is moved to the on position. When the hook switch is in ON position, the phone is now considered to be picked up. The DTMF decoder waits for a certain period of time for the incoming DTMF signal. If the signal is not received, the microcontroller in turn activates the buzzer to indicate a voice call to the receiver.

If the message is received, the DTFM signal is transmitted to the DTMF decoder. The DTMF decoder in turn converts the incoming DTMF signal into BCD of the corresponding key press. This BCD converted signal is fed into the microcontroller of the transceiver, which acts as a latch enabling only one way traffic. This BCD codes are converted into corresponding alpha numeric characters. The ASCII (American Standard Code for Information Interchange) values corresponding to the character is then stored into the EEPROM.The EEPROM is a 8 pin 24c04 IC. It can store up to $ messages. If there is another new message then the oldest message is overwritten. The message which is stored in EEPROM is displayed and read using LCD.The display used here is 16 x 2 LCD(Liquid Crystal Display). That is, it can display message up to a length of 32 characters (16 in each line and hence two lines).There are 4 switches used here which corresponds to each message. That is, if switch 1 is pressed, the first message is displayed and so on.

Detailed Description of the Drawing Figure 1. Block diagram of Mobline The Mobline is the kit which is designed especially for transmission and reception of messages with some special equipment in it. The Figure Contains following particulars having then they are (i) Micro controller IC (202) (ii) Dot matrix alphanumeric LCD Display (203) (iii) Buzzer (204) (iv) EEPROM AT24C16 (205) (v) Crystal & Reset circuit (206) (vi) Switch 1 (207) (vii) Switch 2 (208) (viii) Switch 3 (209) (ix) Regulated power supply (210) (x) Ring detector (211) (xi) DTMF tone decoder(212) (xii) Telephone relay (213).

202: is the heart of MOBLINE. 202 reads the data available at the output of 212 and converts it into equivalent 203

203: This is used at the receiver side instead of seven segment display. This display has two columns of sixteen characters each, that is we can write message up to thirty two characters on it.

204: The 204 used to indicate a voice call if the message is not received for a certain length of time.

205: For storing SMS(Short Message Service), a 205 is used. The 205 is used instead of ROM(Read Only Memory) since we need to a storage device in which the message can be stored and deleted as needed by the users.

206: A Twelve MHz quartz ceramic crystal is used to produce the machine cycle for fetching and executing of instructions.

211 circuits consist of a diode, which is reverse biased, an opto coupler section, a buffer and a timer. When the telephone rings, a voltage is passed through the 211 circuit. The diode, which is reverse biased, transmits during negative pulse and hence the LED(Light Emitting Diode) glows with an increase in the intensity with the amplitude and vice versa. When the LED glows, the opto-transistor conducts and gives the input to the timer. The timer is used to keep track of the duration of the "ring". When the number of rings is three, the controller activates the relay circuit 212 When pressed twelve keys on the 212 keypad, a signal is generated composed of one frequency from a high frequency group and one from low frequency group. These high and low frequency groups are arranged in the rows and columns. When the kit is connected to the telephone line using a relay, one can transmit SMS data to the landline phones. Suppose the pressed number is one, the corresponding frequency for that number is transmitted on the telephone line and is received at the input of 212 decoder IC 8870. This decoder converts the receiving frequency (number) into corresponding binary coded decimal (BCD) output. For e.g., after pressing 1, the output of DTMF decoder is 01 H and microcontroller converts this number into equivalent alphanumeric code (A to Z) and displays on LCD display.

210: For all ICs we need five v D.C. Supply, which can be generated by step down transformer, full wave bridge rectifier, filter condenser and voltage regulator IC 7805.
Figure 2. Frequency of numbers produced table Figure 3.Keymatrix of tone produced table. Figure 4.Flowchart of mobline operation.

Claims:

What is claimed is

1. A mechanism for enhancing the functionalities of existing landlines system comprising of,
One mobline kit connected to the land line telephone, another kit also connected to another landline phone once the landline telephone contacted to another phone, and pre assigned numbers (0-9).

2. Where in the text messages can be transmitted from any distance in the world from mobile to landline.

3. Where in the claim 2, is totally independent, the user need not be present.

4. Where in the claim 3, at a time 32 characters can be displayed.

5. The cost of system is less, compared to other systems it is efficient.