GB2319868A - Pager with two-way communication function - Google Patents

Abstract

A pager is provided suitable for use in a group so that members of the group having similar pagers can call one another by their respective pagers. The pager includes a RF switch 14, a transmitter circuit 30, a receiver circuit 40, an encoder 55, a decoder 60, microprocessor 70 and an I/O device 20. The encoder or/and decoder could be also built into the microprocessor. The RF switch can switch the pager between a receiving and transmitting mode. The encoder can process and encode signal and then send encoded signal to the transmitter circuit for transmitting. The decoder can decode signal received from the receiver circuit. The I/O device 20 includes at least one paging pad for paging other pagers, a buzzer 25 for producing sound when the pager is called, an idle pad 24 for forcing the pager into the stand-by mode, and LED indicators to indicate which other pager of the group is calling.

Description

PAGER WITH TWO-WAY COMMUNICATION FUNCTION The present invention relates to pagers, and more particularly to such a pager which provides a signal receiving function, and a signal transmitting function.

Conventional pagers have only the function of receiving a radio paging signal called through a telephone. There is known a group pager system which comprises a master pager, and a plurality of sub-pagers.

The master pager is comprised of a modulator, an encoder, and a set of paging pads corresponding to the sub-pagers. Each of the sub-pagers is comprised of a demodulator, a decoder, and a buzzer. When one paging pad of the master pager is pressed, the paging signal is decoded by the decoder of the corresponding sub-pager, and the buzzer of the corresponding sub-pager is then driven to buzz. In recent years, local pager systems have become more and more popular. The signal transmitting stations of regular local pager systems have become more and more popular. The signal transmitting stations of regular local pager systems are commonly of low power. However, the pagers of these local pager systems can only receive signal from the signal transmitting station, and cannot transmit signals , such as US. Pat. No. 5 218 344 (Richetts).

Although US Pat. No. 4 882 579 (Siwiak) provides a base station and auto-answer sub-pagers, the sub-pagers cannot page another sub-pager.

For example, when four or five members of a family go to a shopping centre, the father carries the master pager, and each of the other members carries one sub-pager. The father can call any member of the family through the master pager, asking any member or all members to go to the entrance of the shopping centre. However, when one member, for example, one child of the family wishes to purchase a certain item and wants to get the permission from his father, the child cannot use his pager to call the father.

Some people may try to use radio transmitter and receiver devices to solve the aforesaid problem, i.e., let every member of the family have a radio transmitter and receiver device. However, when several radio transmitter and receiver devices are simultaneously used in, for example, a shopping centre, radio signals tend to interfere with one another.

According to a first aspect the present invention consists in a pager comprising means capable of receiving radio frequency signals, means adapted to identify particularly coded radio frequency signals, and means adapted to transmit coded radio frequency signals.

The pager is suitable for use in a group, so that the members of the group can call one another by a respective pager. Because the pager can identify particularly coded radio frequency signals, the user can selectively call the other members of the group.

The pager preferably comprises an antenna, a RF switch, an I/O device, a transmitter circuit, a receiver circuit, a modulator, an encoder, a decoder, an AF amplifier, and a microprocessor, the I/O device being for signal input and output and comprising at least one paging pad, an idle pad, and a buzzer, the receiver circuit, the decoder and the RF amplifier providing the means for receiving radio frequency signals, the transmitter circuit, the modulator and the encoder providing the means for transmitting radio frequency signals, and the microprocessor providing the functions of controlling the operation of the circuit and processing the signal. When the user pages the other pager or pagers through the paging pad or pads, an ID code or a series of ID code is or are provided and sent to the pager or pagers being called. When the paging signal is recognised, the buzzer or the respective pager is driven to buzz, and the user call back by paging the caller's pager, or communicate with the caller directly through a transmitting mode.

According to a second aspect the present invention consists in a pager comprising: a RF switch means for switching the pager between a receiving and transmitting mode to receive and transmit radio frequency signal; a transmitter circuit means for processing low frequency signal into radio frequency signal for transmitting into the air; a receiver circuit means for filtering external radio frequency signal and converting it into low frequency signal; an encoder means for processing and encoding signal and then sending encoded signal to said transmitter circuit means for transmitting; a decoder means for decoding signal received from said receiver circuit means; an I/O device means comprising at least one paging pad for paging other pagers, one buzzer for producing sound when the pager is called, and one idle pad for forcing the pager into a stand-by-mode; and a microprocessor for controlling the circuit and processing signal; wherein said pager is constantly maintained in the stand-by mode for receiving external radio frequency signals; when the user presses one of said at least one paging pad, said pager switched to the transmitting mode by said RF switch means, and then switched back from the transmitting mode to the receiving mode when a code signal has been encoded and transmitted into the air; the pager has at least one identification code for comparison with the code of the signal which is received by said receiver circuit and decoded by said decoder, so that said buzzer is driven to buzz when the code of the received signal is recognised, and then forced to stop from buzzing when said idle pad is pressed.

When pagers in accordance with the present invention are used in a group, the pagers of the members of the group may be identical.

Therefore, the members of the group may make one-to-one, one-tomultiple, multiple-to-multiple communications. Because transmitted signals are respectively carried with an ID code or a series of ID codes, interference between signals is minimised.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a block diagram showing the functional structure of a pager in accordance with the present invention; Fig. 2 is a schematic drawing showing calling between pagers according to the present invention; Fig. 3 is a circuit block diagram; Fig. 4 is a receiving flow chart; Fig. 5 is a transmitting flow chart; Fig. 6 is a circuit diagram of a RF switch; Fig. 7 is a circuit diagram of a front end device; Fig. 8 is a circuit diagram of a demodulator; Fig. 9 is a circuit diagram of an analogue/digital converter; Fig. 10 is a circuit diagram of a modulator Fig. 11 is a circuit diagram of a decoder; Fig. 12 is a circuit diagram of an encoder, and Fig. 13 is a perspective view of the pager Referring to Figure 1, a pager 10 in accordance with the present invention is generally comprised of an antenna 12, a RF switch 14, an I/O device 20, a transmitter circuit 30, a receiver circuit 40, a modulator 50, and encoder 55, a decoder 60, an AF amplifier 65, and a microprocessor 70. The I/O device 20 is for signal input and output. The receiver circuit 40, the decoder 50 and the RF amplifier 65 achieve a signal receiving function. The transmitter circuit 30, the modulator 50 and the encoder 55 achieve a signal transmitting function. The microprocessor 70 provides the functions of controlling the operation of the circuit and processing the signal.

Referring to Figures 2 and 3, regularly the pager 10 is maintained at the stand-by mode, i.e., the power-save mode waiting in readiness for calling.

When the user of the A pager wishes to call the user of the B pager, the user of the A pager shall have to press the B key of the paging pad 22 (the paging pad 22 includes B, C and D keys). When the B key of the A pager is depressed, the microprocessor 70 of the A pager drives the encoder 55 to encode the identification code of the B pager and the identification code of the A pager itself and to send the encoded signal to the transmitter circuit 30, and at the same time the microprocessor 70 switches RF switch 14 to transmitting mode, permitting the encoded signal to be sent out by the transmitter circuit 30 through the antenna 12 via the RF switch 14.

The transmitter circuit 30 is comprised of a power management circuit 31, a RF oscillator 32, and a RF amplifier 33. The power management circuit 31 keeps the transmitter circuit 30 at the power-save mode when it receives no signal, permitting it to be controlled by the microprocessor 70. Because people skilled in the art know the power management circuit 31, the detail circuit is not provided here. The RF oscillator 32 is to add RF carrier to the signal so that the signal can be transmitted into the air. The RF amplifier 33 is to reinforce transmitting signal strength. Because the transmitter circuit 30 can be achieved by known techniques, it is not described herein in detail.

A microphone 21 is provided in the I/O device 20. By means of the control of a talk/listen switch 23, the microprocessor 70 is driven to turn on the microphone 21, or a speaker 27. When the microphone 21 is turned on, the user's voice wave signal is picked up by the microphone 21, then amplified and filtered by the AF-amplifier/filter 52, and then modulated into a corresponding radio signal by the modulator 50, and then transmitted into the air by the transmitter circuit 30 through the antenna 12.

When the user of the B pager is called by the user of the A pager, the radio signal from the A pager is received by the antenna 14 of the B pager, and then sent to the receiver circuit 40. If the received radio signal contains the identification code of the B pager and the identification code of the A pager, a buzzer 25 of the B pager will be driven to produce sound to call the user of the B pager immediately after the received radio signal has been decoded by the decoder 60 of the B pager, and a paging source indicator 26 (which can be a LED indicator device) of the B pager will be driven to show the calling of the A pager when the identification code of the A pager is recognised. At this moment, the user of the B pager can press the idle pad 24 to stop the buzzer 25, and to return the pager 10 to the stand-by mode. The user of the B pager may switch the talk/listen switch 23 to turn on the microphone 21 or the speaker 27. The talk/listen switch 23 can be a single-key design. When the talk/listen switch 23 is maintained depressed, the microprocessor 70 is controlled to drive the AF-amplifier/filter 52 and the microphone 21, allowing the user to use the microphone 21. On the contrary, when the user releases the talk/listen switch 23, the microprocessor 70 is controlled to drive the AF amplifier 65 and the speaker 27. When the user presses on the idle pad 24, the AF-amplifier filter 52 and the AF amplifier 65 are both turned off.

The receiver circuit 40 is comprised of a front end device 41, an A/D converter 42, and a demodulator 43. The front end device 41 is to remove carrier from the signal, and then to send the processed signal to the A/D converter 42 and the demodulator 43. If the identification code of the received signal is recognised, it is then sent by the A/D converter 42 to the AF amplifier 65.

The order of the signal receiving and transmitting actions is controlled by the microprocessor 70. Figure 4 shows an example of receiving flow charts. The pager 10 is normally maintained at the standby-mode. When the pager 10 is called by a calling signal, the buzzer 25 buzzes, and the paging source indicator 26 is driven to indicate the source of the calling signal. At this moment, the user can press the idle pad 24 or the talk/listen switch 23 to turn off the buzzer 25 and the paging source indicator 26. The user can communicate with the caller through the talk/listen switch 23, the speaker 27 and the microphone 21. The user can press the idle pad 24 at any time again to return the stand-by mode.

Figure 5 shows an example of transmitting flow charts. When the user presses the paging pad 22, the corresponding identification code is transmitted to the pager to be called, and at the same time the speaker 27 is turned on. At this moment, the user can press the idle pad 24 to turn off the speaker 27, or switch the talk/listen switch 23 for communication with the user of the pager being called. After communication, the idle pad 24 is pressed again to return the pager to the stand-by mode.

Referring to Figure 6, the RF switch 145 is a control IC (U1, obtained from Sony's CSG 1006N). By means of switching the RF switch 14, the microprocessor 70 achieves controlling the antenna 12 to receive a signal and to transmit a signal.

Referring to Figure 7, the front end device 41 is comprised of a filter circuit 411 and a carrier removing circuit 412, wherein SWA1 and SWA2 are surface filters (which can be, for example, RF1211, RF0211E of Momolithics Inc.); U2 is a RF signal receiving IC (which can be, for example, UAA3201T of Phillips Semiconductor). Either the received radio signal is an identification code or an audio frequency signal, it is filtered by the front end device 41 to remove carrier, and then sent to the A/D converter 42 and the demodulator 43.

Referring to Figure 8, the demodulator 43 comprises a counter 431 which can be of any suitable kind of counter, and a 555 oscillator U3.

Referring to Figure 9, the analogue/digital converter 42 is to covert the received analog signal into a corresponding digital signal, and then to send the digital signal to the decoder 60.

Referring to Figure 10, the modulator 50 comprises a LM317 voltage regulator U4, and a 555 oscillator U5.

Referring to Figure 11, the decoder 60 comprises a MC145028 series/parallel IC U6, which is obtained from Motorola for processing series digital signals into parallel signals, and capable of setting multiple identification codes, and provides code comparing function and logic operation function.

The series digital signal from the analog/digital converter 42 is processed by U6 into a parallel signal. When transmitting an identification code, the identification code of the pager of the caller, the identification code of the pager of the called party and the identification code of the group pagers are preferably combined together. The identification code of the group pagers can be set through a group ID setting pad 81. Because the present invention is suitable for use in groups, every group can set a group ID code for discrimination from the others. When one is called, the decoder 60 immediately checks the group ID case of the received signal. When the group ID code is recognised, the decoder 60 immediately outputs a signal to the microprocessor 70, causing it to drive an alarm control circuit 251 in turning on the buzzer 25, and at the same time the identification code of the caller's pager is recognised and transmitted to the paging source indicator 26 to indicate the source of the calling signal.

When the user presses the idle pad 24 or the talk/listen switch 23, the microprocessor 70 immediately turns off the buzzer 25 through one control line, and drives the decoder 60 through another control line to turn off the paging source indicator 26. Alternatively, the paging source indicator 26 can be directly controlled by the microprocessor 70.

Referring to Figure 12, the encoder 55 comprises an IC U7 which could be a My 145026 IC purchased from Motorrola. The IC U7 can be set to review several ID codes, and to send coded ID signals in a series manner, for example to send the group ID code, the ID code of the caller's pager and the.ID code of the pager of the person being called in sequence. The group ID code can be set through the group ID setting pad 81. the selection of the pager to be called is made through a corresponding paging pad to drive the microprocessor 70 in sending a signal to the IC U7.

The functions of the aforesaid encoder 55 and decoder 60 can be alternatively achieved by the microprocessor 70. Therefore, the encoder 55 and the decoder 60 may be omitted.

Figure 13 shoes the outer appearance of the pager in accordance with embodiment described. The pager may, for example, be used in a pager group which includes four users A, B, C and D. The pager shown in Figure 13 is the A pager for the user A which has B, C, and D paging pads 22. As shown in Figure 13, the antenna 12, the microphone 21, the talk/listen switch 23, the idle pad 24, the buzzer 25, the paging source indicator 26 and the speaker 27 are exposed to the outside.

It is to be understood that the drawings are designed for purposes of illustration only, and are not intended as a definition of the spirit and scope of the invention disclosed.

Claims (8)

1. A pager comprising means capable of receiving radio frequency signals, means adapted to identify particularly coded radio frequency signals, and means adapted to transmit coded radio frequency signals.

2. A pager according to Claim 1 comprising an antenna, a RF switch, an 1/0 device, a transmitter circuit, a receiver circuit, a modulator, an encoder, a decoder, an AF amplifier and a microprocessor, the I/O device being for signal input and output and comprising at least one paging pad, an idle pad and a buzzer, the receiver circuit, the decoder and the AF amplifier providing the means for receiving radio frequency signals, the transmitter circuit, the modulator and the encoder providing the means for transmitting radio frequency signals, and the microprocessor providing the functions of controlling the operation of the circuit and processing the signal.

3. A pager comprising: a RF switch means for switching the pager between a receiving and transmitting mode to receive and transmit radio frequency signal; a transmitter circuit means for processing low frequency signal into radio frequency signal for transmitting into the air; a receiver circuit means for filtering external radio frequency signal and converting it into low frequency signal; an encoder means for processing and encoding signal and then sending encoded signal to said transmitter circuit means for transmitting; a decoder means for decoding signal received from said receiver circuit means; an I/O device means comprising at least one paging pad for paging other pagers, a buzzer for producing sound when the pager is called, and an idle pad for forcing the pager into a stand-by-mode; and a microprocessor for controlling the circuit and processing signal; wherein said pager is constantly maintained in the stand-by mode for receiving external radio frequency signals; when the user presses one of said at least one paging pad, said pager switched to the transmitting mode by said RF switch means, and then switched back from the transmitting mode to the receiving mode when a code signal has been encoded and transmitted into the air; the pager has at least one identification code for comparison with the code of the signal which is received by said receiver circuit and decoded by said decoder, so that said buzzer is driven to buzz when the code of the received signal is recognised, and then forced to stop from buzzing when said idle pad is pressed.

4. A pager according to claim 3 wherein the I/O device further comprises a paging source indicator, which indicates the paging source of the received signal when the pager is called.

5. A pager according to claim 3 wherein the I/O device means further comprises a microphone, and a speaker.

6. A pager according to claim 5 wherein the microphone and the speaker are controlled by a talk/listen switch.

7. A pager according to claim 3 wherein the encoder means and the decoder means are built in said microprocessor.

8. A pager substantially as described herein with reference to the accompanying drawings.