CA2132932A1 - Wireless communication system between keypad and terminal - Google Patents
Wireless communication system between keypad and terminalInfo
- Publication number
- CA2132932A1 CA2132932A1 CA 2132932 CA2132932A CA2132932A1 CA 2132932 A1 CA2132932 A1 CA 2132932A1 CA 2132932 CA2132932 CA 2132932 CA 2132932 A CA2132932 A CA 2132932A CA 2132932 A1 CA2132932 A1 CA 2132932A1
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- Canada
- Prior art keywords
- keypad
- data
- terminal
- entry
- message
- Prior art date
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- Abandoned
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Abstract
A wireless transmitter and receiver pair is connected to the keypad and the base terminal for transmitting and receiving data over a wireless medium and for detecting an alignment signal, which represents alignment between the keypad and the terminal. An indicator circuit provides a message indicative of a state of misalignment to a user of the keypad in response to a failure to detect the alignment signal. A separate wireless position detection system determines the keypads position with respect to the base terminal's zone of transmission, and displays a message to the user for adjusting the position, if necessary. In Point-Of-Sale transaction terminals, the keypad can be used to enter data, while affording the user the comfort and security of being able to hold the keypad close to his or her body.
Description
wTR~r.~,$ COMMUNICATION SYSTEM BETWEBN KEYPAD AND
TERMINAL
Field of the Invention The present invention relates to a wireless communications system interconnecting a hand-held keypad and a base terminal. The invention relates further to such a communications apparatus and method, in which personal or sensitive information is entered by the keypad.
Background of the Invention Keypads are used daily at Point-Of-Sale (POS) bank card payment devices to accept personal bank account debits for purchases. At the POS, the cashier asks the customer for a bank card, slides it through a magnetic stripe reader, and enters the amount of the purchase. The POS device dials up an electronic funds transfer computer network to start the transaction. The customer is given a keypad connected to the POS device by a telephone cord. The keypad includes a small Liquid Crystal Display (LCD), and the first message displayed requests acceptance of the amount of the purchase. The customer presses the OK button in response to the request, and the next message prompts the customer to select a bank account type (i.e. checking, savings, etc.). After account selection, the customer is prompted to enter a Personal Identification Number (PIN). Each numeric key entry appears on the LCD as an asterix, as is common with all Automatic Teller Machines (ATM), in order to prevent bystanders from seeing the PIN. Once the customer presses the enter key after keying the PIN, the device sends a request message to the network to complete the transaction, including all required information, such as account number, amount, account type and PIN. The network transfers the requested amount electronically from the customer's bank account to the store's account in accordance with established procedures and protocols.
As is known in the art, the transmitted data is encrypted to prevent fraud. The keypad is a physically tamper-proof unit which codes the data entered (namely the PIN) before transmitting it to the POS device. In turn the data transmitted from the POS device over telephone lines to the bank's computer is also encrypted. International standards for security and encryption have been established.
A difficulty with such POS devices is the comfort in using the keypad which is connected to the device by a relatively short and fragile cord. The cord often gets in the way and compromises the customer's ability to stand and hold the keypad in a comfortable manner. Security of the transaction may also be compromised by not holding the keypad in a concealed fashion, allowing others to see the PIN
being keyed.
Summary of the Invention Accordingly, it is an object of the invention to provide a secure wireless communications system including a base terminal and a keypad which allows secure entry of data, even in public places, without compromising the speed or efficiency of the data entry and transfer to the base device.
According to the invention, there is provided a wireless directional communication system for communicating data between a hand held keypad and a base terminal comprising wireless means connected to the keypad and the base terminal for transmitting and receiving data over a wireless medium and for detecting an alignment signal when the keypad and the base are substantially aligned with one another along a communications axis, the alignment signal representing alignment of the wireless means for data transmission and reception between the keypad and the terminal, and indicator means for providing a message indicative of a state of misalignment to a user of the keypad in response to a failure to detect the alignment signal.
Preferably, the alignment signal is a continuous pulsed signal having a relatively short duty cycle transmitted by the wireless means from the terminal to the keypad, and data is transmitted between the terminal and the keypad between pulses of the pulsed signal at a fixed delay after the pulses, whereby the alignment signal also synchronizes data transmission between the terminal and the keypad. The indicator means may comprise a display in the keypad, and the message may comprise a text message on the display for prompting the user to re-align the keypad with the terminal. The keypad may also preferably comprise buffer means for storing a sequence of keyed data elements and for causing data representative of the data elements to be sent over the wireless means in response to a key press indicative of completion of entry of the data elements, and the indicator means may be connected to the buffer means, disabled from displaying the message during entry at the keypad of the data elements, and enabled to display the message in response to failure to detect the alignment signal once data entry is completed. In this way, the user will not be prompted to maintain alignment between the keypad and the terminal while holding the terminal in a comfortable position during data entry, until such data entry is completed.
The wireless means are preferably a pair of infra-red transmitters and receivers, although radio or ultrasound transceivers could also be implemented.
The indicator means can produce a visual and/or audio message. The visual message can be a verbal text message or simply an indicator light. The message can be provided either to the user of the keypad directly and/or to a clerk near the user so that the clerk can help the user direct the keypad to the terminal.
Depending on the application, the alignment signal may be a separate signal from the data signal, either transmitted using separate wireless means or the same wireless means used for data, but in a separate time frame. The alignment signal can also be integrated with the data transmission protocol, i.e. the alignment signal may be an acknowledgment signal in response to transmission between the keypad and the terminal. When the alignment signal is a continuous pulsed signal, it can also be used to synchronize data transmission.
The invention also provides a wireless communication system for communicating data between a hand held keypad and a base terminal comprising RF
wireless means connected to the keypad and the base terminal for transmitting and receiving data substantially omnidirectionally, the data being coded according to a predetermined protocol, and closed communication means connected to the keypad and the base for transmitting and receiving information specifying the protocol prior to transmitting and receiving the data.
Brief Description of the Drawings The invention will be better understood by way of the following detailed description of a preferred embodiment of the invention with reference to the appended drawings, in which:
Fig. 1 is a perspective view of a wireless communication system according to the preferred embodiment showing a keypad, its charger-base terminal, and a connector for connecting the base terminal to a point-of-sale (POS) terminal;
Fig. 2 is a block diagram of the circuit for the keypad according to the preferred embodiment;
Fig. 3 is a block diagram of the circuit for the terminal's signal converter according to the preferred embodiment;
Fig. 4 is a signal envelope diagram illustrating infra-red signal transmission between the terminal and the keypad with a periodic alignment code signal;
Fig. 5 is a diagram of a position detection system for determining the position of the keypad with respect to the transmission cone of the base terminal's transmitter and receiver;
and Fig. 6a and 6b show two further embodiments incorporating omni-directional RF data communication with an additional closed communication path for initialization purposes.
DetAile~ Description of the Preferred Embodiment In the preferred embodiment as shown in Fig. 1, the wireless communication system comprises a mobile hand-held wireless keypad terminal 10 and a mobile signal converter base terminal 12 which plugs into a point-of-sale (POS) terminal (not shown~. The base 12 comprises an infra-red transmitter 20 and receiver 22, as well as charging contacts 17 for charging keypad 10 via its contact terminals 16 as the keypad 10 sits on top of the base 12. Base 12 is supplied with DC power from an adapter 18, and plugs into the POS terminal using connector lg. The preferred embodiment is an add on to an existing terminal, allowing the conventional wired hand-held keypad to be replaced by terminals 10 and 12.
The invention is used by retail customers paying for a purchase using their bank cards. The customers give their bank cards to the cashier, and the cashier swipes the card through a magnetic stripe reader.
~ The cashier enters the amount of the purchase at the POS terminal. The customer is then given keypad 10.
The customer points the keypad to base 12 and the first message appears on screen 15, "Amount $XX.XX.
OK?", prompting the customer to press a designated "OK" key on keyboard 14. The next message displayed is "From which account?", prompting the customer to press a bank account type key on keyboard 14, e.g.
"Checking" or "Savings". The next message is "Please enter PIN, then OK.", prompting the customer to enter his or her personal identification number (or code).
Each key press appears on the screen as an asterix to confirm that a key was pressed, while concealing from bystanders the PIN. When the customer finishes entering the PIN, then the OK key is pressed. The customer can hold the keypad 10 in a comfortable and secure manner. If this comfortable manner causes the keypad to lose contact with the base 12, then a message requesting realignment is displayed.
However, if a customer chooses to enter his or her PIN in such a fashion, the key presses will be accepted. Once the OK key is pressed, signaling that the entry is complete and ready to be sent, any misalignment will cause the message to be immediately displayed, and any such misalignment which is prolonged, will cause a cancellation of the transaction.
As shown in Fig. 2, the keypad 10 has an infra-red transmitter 21 and receiver 23 for communicating with the corresponding receiver 22 and transmitter 20, respectively, of the base 12. The data entry keypad 14 and LCD screen display 15 are connected to a microcontroller 30. The microcontroller is powered by a battery 32, recharged by a charging circuit including contacts 16. Controller 30 includes an encryption and decryption program for encrypting entries from the keyboard 14 and for decrypting text messages displayed on screen 15. Data to be transmitted to the base 12 is sent from the controller 30 to a modulator 34 which encodes the digital data into modulated pulses for broadcasting by transmitter 21. The optoelectronic receiver circuit 23 demodulates the infra-red signal sent from the base 12 and sends the received digital data to controller 30. Circuit 23 also checks for an alignment code continuously sent from the base 12 and generates a misalignment signal to controller 30 if the alignment code is not received, as will be explained in better detail below.
Fig. 3 is a block diagram of the data transmission and reception circuit used in the base terminal 12 according to the preferred embodiment.
Encrypted messages from the POS terminal come in connector bus 19 to a serial data port 46. The port 46 relays digital data to a modulator 44 which produces a pulse modulated code signal representing the data, the signal being output to the infra-red optoelectronic transmitter 20. Infra-red light from the keypad terminal 10 is received at a phototransistor whose signal is amplified, filtered and converted into digital data in the remainder of the receiver circuit 22. The digital data is fed to port 46 for transmission over bus 19 to the POS
terminal.
At the start of communication, or even at the start of each transaction, the base 12 transmits a code to keypad 10 which is interpreted by controller to determine a special coding for the signals transmitted from the keypad 10. For example, the coding may comprise data transmission protocol details, bit modulation coding formats, data packet address codes (e.g. a serial number identifier) and data encryption type or key.
The infra-red signal is modulated to represent the data according to conventional protocols, however, in the preferred embodiment, the signal is not continuous, but rather has an envelope as illustrated in Fig. 4. The data part of the signal is limited to 50ms intervals, separated by "silent"
50 ms intervals. In the silent intervals, a short alignment code pulse is transmitted from the base terminal (MSC) 12 to the keypad terminal (MHT) 10.
The keypad 10 also synchronizes its transmission to the base 12 by the alignment code signal and transmits during 50ms bursts as shown. The alignment code signal is unique to the base terminal to avoid a keypad 10 from communicating with a different base terminal in a same store. The controller 30 (Fig. 2) looks at the data received to ensure that the alignment code signal is present between every data group. If the alignment code signal is not present, a misalignment flag is set. Since transmission to the base 12 is to be synchronized with the reception of the alignment code signal, transmission is stopped when the misalignment flag is set.
If the keypad 12 is not in the process of transmitting data, the controller 30 can respond in different ways. In the preferred embodiment, a message is immediately displayed on screen 15, e.g.
"Communication Lost. Please Keep Pointing Toward Base". Other display or entry operations are temporarily suspended. Once the alignment signal is received again, the misalignment flag is cleared, and normal operation of the controller 30 resumes. If the misalignment is prolonged, even the entry operations may be aborted. Data entered in the keypad 10 would then be erased. The keypad would then transmit a "cancel transaction" message to the base 12 as soon as communication is re-established.
In the case that the base 12 is integrated into the POS terminal, messages could be generated for the cashier, so that immediate attention and action is possible.
Fig. 5 shows an embodiment of the invention which includes position determining means. The infra-red transmitter 20 of the base 12 has a cone of transmission 25. Mounted in association with the base 12 are three ultrasound transceivers 52, labeled as C, V and H for center, vertical and horizontal, respectively. Another ultrasound transceiver 50 is mounted to the keypad 10. For clarity of illustration, only the position of the infra-red transmitter 20 and the transceivers 50 and 52 are shown. The position of transceiver 50 is calculated by triangulation after determining the distances between it and each of the three transceivers 52.
Position determination using triangulation is generally known in the art.
In the preferred embodiment, the intelligence of the system is mostly in the microcontroller 30.
Therefore, the distance determination and triangulation is done by the microcontroller. The transceiver 50 can comprise three units receiving at 23kHz, 31kHz and 40kHz. The transceivers 52 can comprise three corresponding units transmitting at the three frequencies and located at C, V and H
respectively, a receiver also being provided at C. A
signal sent from transceiver 50 at the keypad is received at C, and triggers the three transmitters to sent a pulse. Controller 30 times the delay between transmission of the trigger signal to reception of the three pulses. The distances and position of transceiver 50 is then calculated, as is known in the art. If the keypad is near the boundary of cone 25, a warning message can be displayed. The message can indicate the direction in which the keypad needs to be moved to be within the cone 25, relative to the established directions of up-down (V-C) and left-right (H-C). The message could be textual or graphic.
As can be appreciated the trigger signal could be replaced by using the alignment code signal as a timing reference. It would also be possible to trigger transmitter C, V and H with different short delays after the alignment code signal or the ultrasound trigger signal, whereby the three transmitters could operate at the same frequency.
Although the preferred embodiment uses infra-red wireless transmission, ultrasound or RF could alternatively be used. The indicator means according to the preferred embodiment uses an alignment signal and a screen display. It would also be possible to detect misalignment as a result of a failure to receive an acknowledgment signal after sending data.
The message indicating misalignment could be a simple LED with a label identifying its meaning on the keypad 10. The message could also be auditory, namely a gentle beeping sound when misalignment occurs.
For example, spread spectrum RF signaling at a power level of less than lW can be used to provide omni-directional data communication without needing an FCC license. The frequency spectrum can be in the 902 to 928 MHz band. Due to the omni-directionality of the data communication system, the invention provides a closed communication link used for the purposes of a private initialization between the base and the keypad. A closed communication link is one in which the information is not easily intercepted by a receiver in the vicinity of the base and the mobile keypad. As illustrated in Figs. 6a and 6b, a private closed communication link can be a physical contact terminal for a serial communication bus (Fig. 6a) or a short range infra-red or ultrasound communication means operating within a relatively small confined solid angle volume (Fig. 6b). When the cashier swipes the bank card, initialization begins, as in the preferred embodiment. The special coding is not transmitted by the omni-directional RF transmitter 62, but rather is transmitted over the closed communication link. This eliminates the possibility that another receiver in the area listens in on the communication between the keypad 10 and base 12 with a view to analyzing the signals to determine the encryption scheme, and ultimately the PIN codes and possibly customer bank balance information being transmitted.
Once the special coding is transmitted, controller 30 places the prompt message on screen 15 for the customer to begin the transaction process steps. At this point, the RF transmitters and receivers 60 and 62, located in the keypad 10 and base 12 respectively, communicate with each other without needing to maintain alignment between the keypad 10 and the base 12.
TERMINAL
Field of the Invention The present invention relates to a wireless communications system interconnecting a hand-held keypad and a base terminal. The invention relates further to such a communications apparatus and method, in which personal or sensitive information is entered by the keypad.
Background of the Invention Keypads are used daily at Point-Of-Sale (POS) bank card payment devices to accept personal bank account debits for purchases. At the POS, the cashier asks the customer for a bank card, slides it through a magnetic stripe reader, and enters the amount of the purchase. The POS device dials up an electronic funds transfer computer network to start the transaction. The customer is given a keypad connected to the POS device by a telephone cord. The keypad includes a small Liquid Crystal Display (LCD), and the first message displayed requests acceptance of the amount of the purchase. The customer presses the OK button in response to the request, and the next message prompts the customer to select a bank account type (i.e. checking, savings, etc.). After account selection, the customer is prompted to enter a Personal Identification Number (PIN). Each numeric key entry appears on the LCD as an asterix, as is common with all Automatic Teller Machines (ATM), in order to prevent bystanders from seeing the PIN. Once the customer presses the enter key after keying the PIN, the device sends a request message to the network to complete the transaction, including all required information, such as account number, amount, account type and PIN. The network transfers the requested amount electronically from the customer's bank account to the store's account in accordance with established procedures and protocols.
As is known in the art, the transmitted data is encrypted to prevent fraud. The keypad is a physically tamper-proof unit which codes the data entered (namely the PIN) before transmitting it to the POS device. In turn the data transmitted from the POS device over telephone lines to the bank's computer is also encrypted. International standards for security and encryption have been established.
A difficulty with such POS devices is the comfort in using the keypad which is connected to the device by a relatively short and fragile cord. The cord often gets in the way and compromises the customer's ability to stand and hold the keypad in a comfortable manner. Security of the transaction may also be compromised by not holding the keypad in a concealed fashion, allowing others to see the PIN
being keyed.
Summary of the Invention Accordingly, it is an object of the invention to provide a secure wireless communications system including a base terminal and a keypad which allows secure entry of data, even in public places, without compromising the speed or efficiency of the data entry and transfer to the base device.
According to the invention, there is provided a wireless directional communication system for communicating data between a hand held keypad and a base terminal comprising wireless means connected to the keypad and the base terminal for transmitting and receiving data over a wireless medium and for detecting an alignment signal when the keypad and the base are substantially aligned with one another along a communications axis, the alignment signal representing alignment of the wireless means for data transmission and reception between the keypad and the terminal, and indicator means for providing a message indicative of a state of misalignment to a user of the keypad in response to a failure to detect the alignment signal.
Preferably, the alignment signal is a continuous pulsed signal having a relatively short duty cycle transmitted by the wireless means from the terminal to the keypad, and data is transmitted between the terminal and the keypad between pulses of the pulsed signal at a fixed delay after the pulses, whereby the alignment signal also synchronizes data transmission between the terminal and the keypad. The indicator means may comprise a display in the keypad, and the message may comprise a text message on the display for prompting the user to re-align the keypad with the terminal. The keypad may also preferably comprise buffer means for storing a sequence of keyed data elements and for causing data representative of the data elements to be sent over the wireless means in response to a key press indicative of completion of entry of the data elements, and the indicator means may be connected to the buffer means, disabled from displaying the message during entry at the keypad of the data elements, and enabled to display the message in response to failure to detect the alignment signal once data entry is completed. In this way, the user will not be prompted to maintain alignment between the keypad and the terminal while holding the terminal in a comfortable position during data entry, until such data entry is completed.
The wireless means are preferably a pair of infra-red transmitters and receivers, although radio or ultrasound transceivers could also be implemented.
The indicator means can produce a visual and/or audio message. The visual message can be a verbal text message or simply an indicator light. The message can be provided either to the user of the keypad directly and/or to a clerk near the user so that the clerk can help the user direct the keypad to the terminal.
Depending on the application, the alignment signal may be a separate signal from the data signal, either transmitted using separate wireless means or the same wireless means used for data, but in a separate time frame. The alignment signal can also be integrated with the data transmission protocol, i.e. the alignment signal may be an acknowledgment signal in response to transmission between the keypad and the terminal. When the alignment signal is a continuous pulsed signal, it can also be used to synchronize data transmission.
The invention also provides a wireless communication system for communicating data between a hand held keypad and a base terminal comprising RF
wireless means connected to the keypad and the base terminal for transmitting and receiving data substantially omnidirectionally, the data being coded according to a predetermined protocol, and closed communication means connected to the keypad and the base for transmitting and receiving information specifying the protocol prior to transmitting and receiving the data.
Brief Description of the Drawings The invention will be better understood by way of the following detailed description of a preferred embodiment of the invention with reference to the appended drawings, in which:
Fig. 1 is a perspective view of a wireless communication system according to the preferred embodiment showing a keypad, its charger-base terminal, and a connector for connecting the base terminal to a point-of-sale (POS) terminal;
Fig. 2 is a block diagram of the circuit for the keypad according to the preferred embodiment;
Fig. 3 is a block diagram of the circuit for the terminal's signal converter according to the preferred embodiment;
Fig. 4 is a signal envelope diagram illustrating infra-red signal transmission between the terminal and the keypad with a periodic alignment code signal;
Fig. 5 is a diagram of a position detection system for determining the position of the keypad with respect to the transmission cone of the base terminal's transmitter and receiver;
and Fig. 6a and 6b show two further embodiments incorporating omni-directional RF data communication with an additional closed communication path for initialization purposes.
DetAile~ Description of the Preferred Embodiment In the preferred embodiment as shown in Fig. 1, the wireless communication system comprises a mobile hand-held wireless keypad terminal 10 and a mobile signal converter base terminal 12 which plugs into a point-of-sale (POS) terminal (not shown~. The base 12 comprises an infra-red transmitter 20 and receiver 22, as well as charging contacts 17 for charging keypad 10 via its contact terminals 16 as the keypad 10 sits on top of the base 12. Base 12 is supplied with DC power from an adapter 18, and plugs into the POS terminal using connector lg. The preferred embodiment is an add on to an existing terminal, allowing the conventional wired hand-held keypad to be replaced by terminals 10 and 12.
The invention is used by retail customers paying for a purchase using their bank cards. The customers give their bank cards to the cashier, and the cashier swipes the card through a magnetic stripe reader.
~ The cashier enters the amount of the purchase at the POS terminal. The customer is then given keypad 10.
The customer points the keypad to base 12 and the first message appears on screen 15, "Amount $XX.XX.
OK?", prompting the customer to press a designated "OK" key on keyboard 14. The next message displayed is "From which account?", prompting the customer to press a bank account type key on keyboard 14, e.g.
"Checking" or "Savings". The next message is "Please enter PIN, then OK.", prompting the customer to enter his or her personal identification number (or code).
Each key press appears on the screen as an asterix to confirm that a key was pressed, while concealing from bystanders the PIN. When the customer finishes entering the PIN, then the OK key is pressed. The customer can hold the keypad 10 in a comfortable and secure manner. If this comfortable manner causes the keypad to lose contact with the base 12, then a message requesting realignment is displayed.
However, if a customer chooses to enter his or her PIN in such a fashion, the key presses will be accepted. Once the OK key is pressed, signaling that the entry is complete and ready to be sent, any misalignment will cause the message to be immediately displayed, and any such misalignment which is prolonged, will cause a cancellation of the transaction.
As shown in Fig. 2, the keypad 10 has an infra-red transmitter 21 and receiver 23 for communicating with the corresponding receiver 22 and transmitter 20, respectively, of the base 12. The data entry keypad 14 and LCD screen display 15 are connected to a microcontroller 30. The microcontroller is powered by a battery 32, recharged by a charging circuit including contacts 16. Controller 30 includes an encryption and decryption program for encrypting entries from the keyboard 14 and for decrypting text messages displayed on screen 15. Data to be transmitted to the base 12 is sent from the controller 30 to a modulator 34 which encodes the digital data into modulated pulses for broadcasting by transmitter 21. The optoelectronic receiver circuit 23 demodulates the infra-red signal sent from the base 12 and sends the received digital data to controller 30. Circuit 23 also checks for an alignment code continuously sent from the base 12 and generates a misalignment signal to controller 30 if the alignment code is not received, as will be explained in better detail below.
Fig. 3 is a block diagram of the data transmission and reception circuit used in the base terminal 12 according to the preferred embodiment.
Encrypted messages from the POS terminal come in connector bus 19 to a serial data port 46. The port 46 relays digital data to a modulator 44 which produces a pulse modulated code signal representing the data, the signal being output to the infra-red optoelectronic transmitter 20. Infra-red light from the keypad terminal 10 is received at a phototransistor whose signal is amplified, filtered and converted into digital data in the remainder of the receiver circuit 22. The digital data is fed to port 46 for transmission over bus 19 to the POS
terminal.
At the start of communication, or even at the start of each transaction, the base 12 transmits a code to keypad 10 which is interpreted by controller to determine a special coding for the signals transmitted from the keypad 10. For example, the coding may comprise data transmission protocol details, bit modulation coding formats, data packet address codes (e.g. a serial number identifier) and data encryption type or key.
The infra-red signal is modulated to represent the data according to conventional protocols, however, in the preferred embodiment, the signal is not continuous, but rather has an envelope as illustrated in Fig. 4. The data part of the signal is limited to 50ms intervals, separated by "silent"
50 ms intervals. In the silent intervals, a short alignment code pulse is transmitted from the base terminal (MSC) 12 to the keypad terminal (MHT) 10.
The keypad 10 also synchronizes its transmission to the base 12 by the alignment code signal and transmits during 50ms bursts as shown. The alignment code signal is unique to the base terminal to avoid a keypad 10 from communicating with a different base terminal in a same store. The controller 30 (Fig. 2) looks at the data received to ensure that the alignment code signal is present between every data group. If the alignment code signal is not present, a misalignment flag is set. Since transmission to the base 12 is to be synchronized with the reception of the alignment code signal, transmission is stopped when the misalignment flag is set.
If the keypad 12 is not in the process of transmitting data, the controller 30 can respond in different ways. In the preferred embodiment, a message is immediately displayed on screen 15, e.g.
"Communication Lost. Please Keep Pointing Toward Base". Other display or entry operations are temporarily suspended. Once the alignment signal is received again, the misalignment flag is cleared, and normal operation of the controller 30 resumes. If the misalignment is prolonged, even the entry operations may be aborted. Data entered in the keypad 10 would then be erased. The keypad would then transmit a "cancel transaction" message to the base 12 as soon as communication is re-established.
In the case that the base 12 is integrated into the POS terminal, messages could be generated for the cashier, so that immediate attention and action is possible.
Fig. 5 shows an embodiment of the invention which includes position determining means. The infra-red transmitter 20 of the base 12 has a cone of transmission 25. Mounted in association with the base 12 are three ultrasound transceivers 52, labeled as C, V and H for center, vertical and horizontal, respectively. Another ultrasound transceiver 50 is mounted to the keypad 10. For clarity of illustration, only the position of the infra-red transmitter 20 and the transceivers 50 and 52 are shown. The position of transceiver 50 is calculated by triangulation after determining the distances between it and each of the three transceivers 52.
Position determination using triangulation is generally known in the art.
In the preferred embodiment, the intelligence of the system is mostly in the microcontroller 30.
Therefore, the distance determination and triangulation is done by the microcontroller. The transceiver 50 can comprise three units receiving at 23kHz, 31kHz and 40kHz. The transceivers 52 can comprise three corresponding units transmitting at the three frequencies and located at C, V and H
respectively, a receiver also being provided at C. A
signal sent from transceiver 50 at the keypad is received at C, and triggers the three transmitters to sent a pulse. Controller 30 times the delay between transmission of the trigger signal to reception of the three pulses. The distances and position of transceiver 50 is then calculated, as is known in the art. If the keypad is near the boundary of cone 25, a warning message can be displayed. The message can indicate the direction in which the keypad needs to be moved to be within the cone 25, relative to the established directions of up-down (V-C) and left-right (H-C). The message could be textual or graphic.
As can be appreciated the trigger signal could be replaced by using the alignment code signal as a timing reference. It would also be possible to trigger transmitter C, V and H with different short delays after the alignment code signal or the ultrasound trigger signal, whereby the three transmitters could operate at the same frequency.
Although the preferred embodiment uses infra-red wireless transmission, ultrasound or RF could alternatively be used. The indicator means according to the preferred embodiment uses an alignment signal and a screen display. It would also be possible to detect misalignment as a result of a failure to receive an acknowledgment signal after sending data.
The message indicating misalignment could be a simple LED with a label identifying its meaning on the keypad 10. The message could also be auditory, namely a gentle beeping sound when misalignment occurs.
For example, spread spectrum RF signaling at a power level of less than lW can be used to provide omni-directional data communication without needing an FCC license. The frequency spectrum can be in the 902 to 928 MHz band. Due to the omni-directionality of the data communication system, the invention provides a closed communication link used for the purposes of a private initialization between the base and the keypad. A closed communication link is one in which the information is not easily intercepted by a receiver in the vicinity of the base and the mobile keypad. As illustrated in Figs. 6a and 6b, a private closed communication link can be a physical contact terminal for a serial communication bus (Fig. 6a) or a short range infra-red or ultrasound communication means operating within a relatively small confined solid angle volume (Fig. 6b). When the cashier swipes the bank card, initialization begins, as in the preferred embodiment. The special coding is not transmitted by the omni-directional RF transmitter 62, but rather is transmitted over the closed communication link. This eliminates the possibility that another receiver in the area listens in on the communication between the keypad 10 and base 12 with a view to analyzing the signals to determine the encryption scheme, and ultimately the PIN codes and possibly customer bank balance information being transmitted.
Once the special coding is transmitted, controller 30 places the prompt message on screen 15 for the customer to begin the transaction process steps. At this point, the RF transmitters and receivers 60 and 62, located in the keypad 10 and base 12 respectively, communicate with each other without needing to maintain alignment between the keypad 10 and the base 12.
Claims (17)
1. A wireless directional communication system for communicating data between a hand held keypad and a base terminal comprising:
wireless means connected to the keypad and the base terminal for transmitting and receiving data over a wireless medium and for detecting an alignment signal when the keypad and the base are substantially aligned with one another along a communications axis, said alignment signal representing alignment of said wireless means for data transmission and reception between said keypad and said terminal; and indicator means for providing a message indicative of a state of misalignment to a user of the keypad in response to a failure to detect said alignment signal.
wireless means connected to the keypad and the base terminal for transmitting and receiving data over a wireless medium and for detecting an alignment signal when the keypad and the base are substantially aligned with one another along a communications axis, said alignment signal representing alignment of said wireless means for data transmission and reception between said keypad and said terminal; and indicator means for providing a message indicative of a state of misalignment to a user of the keypad in response to a failure to detect said alignment signal.
2. The system as claimed in claim 1, wherein:
said alignment signal is a continuous pulsed signal having a relatively short duty cycle transmitted by the wireless means from said terminal to said keypad; and data is transmitted between said terminal and said keypad between pulses of said pulsed signal at a fixed delay after said pulses, whereby said alignment signal also synchronizes data transmission between said terminal and said keypad.
said alignment signal is a continuous pulsed signal having a relatively short duty cycle transmitted by the wireless means from said terminal to said keypad; and data is transmitted between said terminal and said keypad between pulses of said pulsed signal at a fixed delay after said pulses, whereby said alignment signal also synchronizes data transmission between said terminal and said keypad.
3. The system as claimed in claim 2, wherein said indicator means comprise a display in said keypad, said message comprising a text message on said display for prompting said user to re-align said keypad with said terminal.
4. The system as claimed in claim 3, wherein:
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
5. The system as claimed in claim 1, wherein said indicator means comprise a display in said keypad, said message comprising a text message on said display for prompting said user to re-align said keypad with said terminal.
6. The system as claimed in claim 1, wherein:
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
7. The system as claimed in claim 2, wherein:
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
said keypad comprises buffer means for storing a sequence of keyed data elements and for causing data representative of said data elements to be sent over said wireless means in response to a key press indicative of completion of entry of said data elements; and said indicator means is connected to said buffer means, is disabled from displaying said message during entry at said keypad of said data elements, and is enabled to display said message in response to failure to detect said alignment signal once data entry is completed, whereby said user will not be prompted to maintain alignment between said keypad and said terminal while holding said terminal in a comfortable position during data entry, until such data entry is completed.
8. The system as claimed in claim 4, further comprising data encryption means for encrypting data before transmission between said keypad and said terminal, said keypad being used for entry of a Personal Identification Number (PIN).
9. The system as claimed in claim 6, further comprising data encryption means for encrypting data before transmission between said keypad and said terminal, said keypad being used for entry of a Personal Identification Number (PIN).
10. The system as claimed in claim 7, further comprising data encryption means for encrypting data before transmission between said keypad and said terminal, said keypad being used for entry of a Personal Identification Number (PIN).
11. The system as claimed in claim 1, further comprising means for detecting a position of the keypad with respect to the wireless means at the base terminal, and means for signaling the user to correct said position by movement in a particular direction.
12. The system as claimed in claim 11, wherein said position detecting means comprise a triad of ultrasonic transducers connected to the base terminal, at least one ultrasonic transducer mounted on the keypad, means for calculating distances between the triad of transducers and the keypad transducer, and means for calculating said position based on said calculated distances.
13. A wireless communication system for communicating data between a hand held keypad and a base terminal comprising:
RF wireless means connected to the keypad and the base terminal for transmitting and receiving data substantially omnidirectionally, said data being coded according to a predetermined protocol; and closed communication means connected to the keypad and the base for transmitting and receiving information specifying said protocol prior to transmitting and receiving said data.
RF wireless means connected to the keypad and the base terminal for transmitting and receiving data substantially omnidirectionally, said data being coded according to a predetermined protocol; and closed communication means connected to the keypad and the base for transmitting and receiving information specifying said protocol prior to transmitting and receiving said data.
14. The system as claimed in claim 13, wherein said closed communication means comprise infra-red transceiver means.
15. The system as claimed in claim 13, wherein said closed communication means comprise ultrasound transceiver means.
16. The system as claimed in claim 13, wherein said closed communication means comprise a serial communications link including a contact terminal provided on an exterior of the keypad and a complementary contact terminal provided on a charger mount of said base.
17. The system as claimed in claim 13, wherein said RF means broadcast and receive low power spread spectrum signals in a band near 950 MHz.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US31149894A | 1994-09-23 | 1994-09-23 | |
| US311,498 | 1994-09-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2132932A1 true CA2132932A1 (en) | 1996-03-24 |
Family
ID=23207164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2132932 Abandoned CA2132932A1 (en) | 1994-09-23 | 1994-09-26 | Wireless communication system between keypad and terminal |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2132932A1 (en) |
-
1994
- 1994-09-26 CA CA 2132932 patent/CA2132932A1/en not_active Abandoned
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |