GB2267166A - Pager with security - Google Patents

Abstract

In a method for operational security in a pager, to start using the pager, the owner has to key in a specified personal password. The pager begins to perform various functions only if the password is correct. Otherwise, either owing to the password being keyed in wrongly for a predetermined number of times, or on receipt of a paging message containing a "freeze" command, the pager automatically enters a first frozen state in which regular functions become temporarily inoperative. Said frozen state will be ended, if the owner keys in a correct personal password, and the pager will resume its normal performance, but if the personal password is wrongly keyed in for a predetermined number of times, the pager will automatically enter a second frozen state in which all functions become temporarily inoperative. The last situation can be ended only by use of a paging centre's defreeze apparatus.

Description

SPECIFICATION t4ETHOD FOR PAGER OPERATION SECURITY AND PAGER ADAPTED TO THE METHOD FOR PAGER OPERATION SECURITY Technical field The present invention relates in general to a pager, or to an electronic product equipped with a pager. It relates in particular to a method for pager operation security (MPOS) and to a pager adapted to said MPOS.

Background of the invention A simple control key is generally provided on any popular pager model, mainly for controlling and stopping the beeping or vibration yenerated after the pager picks up a call. This is because the pager, after intercepting a call signal, has to alert its owner through setting off an alarm by way of beeping or vibrating, in addition to the instant visual display on pager screen. More keys are provided on a more complicated pager model though, additional keys are merely used to pick up various kinds of information such as news, personal messages, and to scroll the screen display upward and downward for viewing lengthy information, etc.As to the functions of controlling a screen display, of enciphering a message before dispatch, and of direct access to a certain piece of information, realisation of these functions on pagers has not been realized, especially realization through a simple but functionally powerful, widely applicable method of numeric key control, has not been commercially available.

On the other hand, attributed to the advent of miniaturized electronic components, a small sized pager today can perform increasingly powerful functions. In the past, only one kind of pager (tone-only-pager) was available, that had the function of giving alarming tones; then a numeric-pager was available, capable of isplaying name code and phone numbers up to 10-15 digits. At present, the pagers available in our market are alpha numeric-pagers, providing large size screen LCD display and capable of displaying the whole or an interpretation of a message.

The messages received are no longer restricted to personal messages, but valuable public information as well. The received messages and information are stored in a memory. This design will, when the owner mislays his pager, result in the received and stored contents being leaked out, or, when the pager falls into the hands of an unauthorized person, allows that person to use the pager to obtain information immediately. All today's models provide no protection of this nature.

In view of this, the inventor proposes for his pagers a Method of Numeric Key Control (MNKC), and at the same time, also proposes thisMPOS. The MNKC aims at realisation of a variety of new control functions on a pager, through manipulating the numeric keys on keyboard, in association, with some other functional keys. The EiNKC is easy to operate and makes wide applications. For example, it is possible for the pager, after its intercepting a call signal, to temporarily suppress its message display, pending the owner issuing a specific password, to prevent the screen display message being visible and leaked out to another nearby person.It is possible for the owner to assign his own information deciphering keyword, to cryptograph the message before the time of dispatch, so that the message is not coded in a generally known code like ASCII, for fear of the same message being intercepted by another receiver.

And, by the MNKC, information may be retrieved by inputing directly its specified number and the information is categorised according to the digits (unit, ten, hundred, and thousand digits) of the number to save time in searching and reading the information, and especially, to keep owner's information under secret protection both during reading and during dispatching.

The MPOS of this invention has combined the features of the NMKC, to enable the pager, under certain conditions, like the pager being accidentally mislaid by the owner or being used by an unauthorized person, to enter a so-called frozen state following a predetermined control process, namely, to enter a state in which the normal paging functions or all functions will temporarily become inoperative; and under other conditions, like the pager being recovered after being mislaid, may be defrozen following a predetermined control process, namely, the frozen functions of the pager may completely be restored.Thus, the owner may appreciate the ideal, reliable and secure performance of a pager operation. Summary of the invention Therefore the object of this invention is to provide a MPOS for a pager and for an electronic product equipped with a pager, and to provide a pager adapted to MPOS. At the time of the owner using the pager, once the situation occurs that may lead to a leak out of information, the pager will, automatically or under the owner's control, enter a frozen state wherein normal functions temporarily become inoperative, and once this emergency situation is over, the pager will be able to return to a normal state through a controlled process.

The technical solution for carrying out the invented method and pager are the following.

A method for pager operation security (MPOS), said pager comprising both numeric keys and control keys, said method comprising the following steps: a. the owner of the pager selecting a predetermined paging functions by manipulating the numeric and control keys, rendering the pager to await the input of a personal password; b. the owner inputting, through manipulating the numeric keys, a predetermined numerical sequence representative of a personal password; c. the pager checking the validity of the input personal password; c-l. if valid, then pager performing selected function; c-2. if invlaid, the pager awaiting further input of a password, and repeating the password cheching process, until all the passwords inputted for n consecutive times being invalid (where n being an integer greater than 1), then the pager entering a first frozen state; (or the pager entering a first frozen state simply as soon as paging messages carrying a freeze command having been received by the pager;) d. the owner selecting a de-freeze function, through maniputating the numeric keys and function keys, rendering the pager to await the input of a personal password; e. the owner inputting, through maniputating the numeric keys, a predetermined numerical sequence representative of a personal password; f. the pager checking the validity of the input personal password: f-l. if invalid, the pager awaiting further input of a password, and repeating the process of password checking until all the passwords inputted for n consecutive times being invalid (where n being an integer greater than 1), then the pager entering a second frozen state; f-2. if valid, the pager may be defrozen, and its operation may return to normalcy; g. the second frozen state being ended by means of a defreeze apparatus at the paging centre, to enable the pager to return to normalcy.

A poser adapted to the MPOS, said pager comprising: RF receiver, decoder, CPU, memory, display screen and control keyboard, characterised in: said control keyboard comprising numeric keys for numeric inputs and functional controls, and control keys for operation in associstion with numeric keys; said RF receiver comprising demodulating means for demodulating the information codes and address codes received in modulated signals, and control means for temporarily freezing all receiving functions of the RF receiver after the CPU having received a freeze command or after the pager having entered a frozen state upon receiving of inputting cipher keyword; said memory comprising storage means for a. changeable personal password, storage means for a changeable address code, storage means for a changeable decipher keyword, and storage means for storing personal messages and public information; siad CPU comprising a password checking means for checking the keyboard input personal password against the personal password stored in the memory so as to effect controlling the pagerls execution or freezing its normal operation; a freezing means for decoding the freeze signal in the received signal, and for controlling the pager and freezing its normal operation according to the decoded freeze command; a controlling means for updating the stored data in said storage means for personal password according to keyboard input; a control means for, after the pager having entered a state, in which all normal operational function are frozen, checking the keyboard input personal password against the stored personal password, and controlling the pager in recovering its normal operation functions, or in recovering its normal operational functions only by means of the de-freeze apparatus at the paging center; a means for controlling the diaplay device not to instantly display at a display in secrecy mode but first request the owner to input passwords; and a means for controlling the RF receiver, keyboard, display screen, and other input/ouput devices to temporarily freeze their functional operation in a "frozen" state.

Brief description of the drawings Fig. 1 is the front view of a pager adaptable to this invention.

Fig e 2 is a flowchart showing the control in a frozen state on a pager that realizes the invented MPOS.

Fig. 3 is a flowchart showing the principles of the pager message display in secrecy as being realized on a pager adapted to MPOS.

Fig. 4 is a flowchart showing the principles of changing a personal pager password as being realized on a pager adapted to MPOS.

Fig. 5 is a flowchart showing the principles of changing a pager decipher keyword as being realized on a pager adapted to MPOS.

Fig. 6 is a flowchart showing the principles of changing a pager address code as being realized on a pager adapted to MPOS.

Fig. 7 is a block diagram showing the principles of configuring a pager adapted to the invented MPOS.

Detailed description of the preferred embodiments In Fig.11 the front view of a pager using the invented NMKC, has three keys, labelled respectively, Upshift key 1, downshift key 2, overleaf key 3, which may perform the functions of overleaf/enterO In addition, there are ten numeric keys also performing the functions of numeric/functionu, being labelled respectively with numbers 0-9. The basic functions are: KEY s N ~ NAME FUNCTION

numeric/function numeric input or function selection keys (in association with enter key).

upshift key selective display of preceding message item

downshift key selective display of succeeding message item

overleaf/enter message length exceeding screen key display, this key allows reading of next page. Where no message is received, this key is used in association with the 0-9 keys as either numeric keys or function keys.

Pressing any one numeric key (one of the 0-9 keys) represents an assigned function. For example, numeric key fll is assigned a pass word processing function. When numeric key S is followed by the pressing of E key, a functional command for processing a password is activated.

A general type of pager issues a beeping sound or vibrating alert or pilot lamp blinking, when it intercepts a call signal, and displays a call message on the pager's LCD screen. According to an aspect of the present invention, the owner uses the numeric keys to enter his password (a digit or more) to control whether the received message is to be instantly displayed on screen. After the pager gets the message the pager only beeps/vibrates and blinks its pilot lamps, and no message is displayed. When the owner enters a correct password, reading of the message on display screen is then allowable. If the password is incorrectly entered for a number of times, the pager automatically enters a "frozen state", namely, all normal functions of the pager are temporarily frozen to prevent other persons from using the pager.

Fig. 2 is a flowchart for controlling the pager in frozen state as being realized on a pager adapted to the invented MPOS. (The whole flowchart process of Fig. 2 is composed of Fig. 2(a) on drawing P.

2, and of Fig. 2(b) on drawing P. 3, both Figs. 2(a) and 2(b) joining together through a common point "a" in the flowchart).

To start using a pager, the owner selects one from a set of predetermined paging functions (e.g., displaying the received paging message on the screen of a pager) through maniputating the numeric keys and control keys. At this time, the pager awaits the owner to enter his personal password before performing any function.

On receipt of the entered password, the CPU of the pager and also the related checking and comparing means begin to compare the entered numerical sequence with the stored numerical sequence in pager1 5 memory representative of the expected password, and to identify the owner. As being set in the software program, provided the entered password is correct, then the pager allows to perform the selected predetermined function (e.g., instant display of the paging message on a pager screen); if, however, the entered password is incorrect, then the pager will not perform the selected function, but will await a second entering of password by the owner, and repeat the aforesaid password checking process.In the case of the password being entered incorrectly for a number of consecutive times, the pager will enter a preliminary (or first) frozen state, namely, all normal functions'of the pager temporarily become inoperative (e.g., excepting the operation of de-freezing the pager, all other functional operations will temporarily be prohibited).

As regards the reasons for the pager entering its frozen state, a general consideration obviously is for the owner to prevent the pager being used by an unauthorized person to illegally obtain the owner's paging information in case the pager is mislaid. If the operator of the pager now is not its real owner, resulting in entering a password incorrectly even after a specified number of times, the pager then automatically freezes itself to meet the owner's security requirement. In addition, this invention provides facilities for pager owner to cope with specific situations (e.g., discovering that his pager has been mislaid), by notifying the paging center on his own initiative following some kind of procedure, and requesting the paging center to transmit a freeze signal in a message format to the pager. This is possible because the signal sent from any paing station to any pager can incorporate a pager address code and some messages for the owner. The commonly used paging format POCSAG code adopts a BCE (31, 21) format, which is a 31-bit word format consisting of 21 information bits, 10 redundancy check bits and 1 even parity bit. The first information bit is for identifying whether the information is an address or message for owner, hence only 20 bits of a word is informative.

The freeze command is sent from a paging station and presented in full or in part of the information bits, so that the pager can identify the "freeze" command from the specific codes received, and enters a frozen state accordingly.

Therefore7 under any one of th aforesaid situations our invention requires the pager to enter a first frozen state as directed, to satisfy the owner's requirement of using the pager in secrecy.

The next thing to happen could be the pager in its first frozen state being found and used again by the owner, and the owner wishes the pager to resume its normal operations. The owner may first select the de-freeze function by operating on numeric keys and on functional keys, then at this time the pager awaits entering of a personal password by the owner.

The owner then enters his personal password through numeric keys.

The pager checks the validity of the entered personal password. If invalid, then defreezing is impossible. If the entered password are invalid for many times (sufficiently indicating the user of the pager not being a real owner), the pager automatically enters a second (or higher) frozen state, wherein all paging functions become temporarily inoperative so that it is not possible to defreeze by any operation on the pager alone. The pager must be sent to a paging center, to recover the functions by means of a special defreeze apparatus.

Each pager performs its various functions through a CPU and its stored software. The software includes the execution of programs and commands in the frozen states. For example, on receipt of a certain command, the pager can only display public informations but not personal messages. For yet another example, on receipt of a certain command, it can not receive any more new personal messages. Under certain conditions, the pager may be de-frozen by entering a command through numeric keys, and under other conditions, de-freezing must be done by the paging center. These are Oll included in the execution programs.

For example, let us assume functional numeric key No. 3, and personal password "2482" on said numeric keys are for defreezing.

On recovering a lost pager, the owner first presses numeric key "3", then the "enter" key, directing the pager to enter a state awaiting a personal password. The owner presses "2482" on the numeric keys to enter his personal password. After verifying the personal password, the pager immediately resumes its normal operation. If the passwords entered are incorrect for a number of times, then the pager automatically enters the aforesaid second frozen state. Defreezing in this state to restore the operation of normal functions, can only be achieved by connecting the pager to the paging center's special defreezing apparatus, via a special interface port, and by entering a signal representative of a specified program.

Fig. 3 is a flowchart showing the principles of the method of pager message display in secrecy as being realized on a pager adapted to said invention.

The program begins with the pager picking up a call signal, and executing the beeping/vibrating and blinking process. At this time, the internal pager program begins the step to monitor a possible key controlled input, like input from upshift key, downshift key, and other keys being assigned with specific functions, and these input commands are not immediately executed pending on the result of a checking step on whether a password has just been entered. If yes, then check the correctness of the password, and message may be displayed on an affirmative outcome of the check. Otherwise, the program returns to the step of monitoring key controlled input and password entering.If the password is entered consecutively wrongly for a number of times (like for n times, where n is an integer greater than 1), then the operator of the pager is unlikely the owner, and the pager enters automatically a "frozen state", and the normal paging functions becomes inoperative.

Fig. 4 is a flowchart showing the principles of changing a personal paging password as being realized on a pager adapted to said invention.

The PASSWORD may be changed by the owner. When changing, the old password (PASSWORD1) is entered first, followed by a new password (PASSWORD2). Thus the pager password PASSWORDl is replaced by PASSWORD2. At the beginning of the program, after selecting the above-mentioned function of password processing, the original password is entered, and the program checks this password. If it is correct then the next step accepts a new password, which will be in effect immediately after being entered. That is to say, press two keys to specify the password processing function, followed by entering the old password and new password through numeric keys, thus to allow the new password to immediately replace the old one.

If the original password is entered wrongly after all n consecutive times, the operator of the page is unlikely the owner, automatically the pager goes into its frozen state.

Fig. 5 is a flowchart illustrating the principles of a pager decipher keyword as being realized on a pager adapted to said invention.

A paging station sends a call signal to a pager, the signal information consists of a pager address code, and the message for the owner. A commonly used paging code POCSAG (Post Office Code Standardization Advisory Group) adopts the format BCH(31,21), namely, a word is made up of totally 32 bits, with 21 information bits, 10 redundanct check bits, and 1 even parity bit. Of the information bits, the first bit is a message bit for identifying whether the information is an address code or owner message, hence only 20 bits per word are allowed for owner's information, the information is enciphered by the paging station before transmission, the pager automatically deciphers . the received information, with a decipher keyword mutually agreed upon in contract by the owner and the paging station. For example, 3728 may be chosen as a decipher keyword.The owner has to enter this keyword through the numeric keys, and store it in the pager for later deciphering purposes. The paging station enciphers, with the corresponding keyword, all information sent to the owner.

Therefore each pager is distinctly enciphered to achieve a secrecy meeting individual needs.

The program begins with the selection of the function of entering a decipher keyword. A password is entered first so that the program checks the validity of the password. Based on an affirmative outcome from the check, the next step is executed to accept a new decipher keyword, and the pager henceforth decipher messages with it. In case that the password is entered wrongly for n consecutive times the operator is unlikely the owner of the pager, then the pager automatically enters a first frozen state.

Fig. 6 is a flowchart illustrating the principles of changing a pager address code as being realized on a pager adapted to said invention.

The pager address codes normally are assigned by the paging station and are stored fixedly in the pager, and no change is possible without permission. Therefore as the owner wishes to change a pager or to purchase a pager, a new pager must be registered at a paging station, or an unwanted pager must be deregistered and the original address must be written down into the new pager at the same paging station. The owner can not change the pager'soriginal address or enter a new address. A pager with numeric keys can carry out an easy way of changing the address. When the owner s employs this pager, he can enter a new address code of the pager using numeric keys by himself in order to use the original pager continuously without sending the pager to a paging station for changing the address code.

The program begins with the selection of the function of an address input, and the entering of a password. The program checks the correctness of the password. On the basis of an affirmative reply, the screen shows the original address code of the pager. Then the program requires a confirmation that the old address needs to be changed, according to whether the upshift key or the downshift key is pressed. If the downshift key is pressed, then the original address should remain unchanged and the pager should continue to use the original address for reception. If the upshift key is pressed, then the address should be changed, then the pager is ready to accept the input of a new address, and henceforth the pager receives messages at the new address.At the time of entering a password, if the passwords are found consecutively wrong for n times, then the user of the pager is probably not the owner, the pager will automatically enter a first frozen state.

Fig. 7 is a block diagram showing the principles of configurating a pager according to the said invention in association with the MNKC. As shown in the figure, the pager comprises antenna, RF receiver, decoder, CPU, LCD display screen, memory, low battery detector, clock, and other inputloutput devices like loudspeaker, vibrator, pilot lamp, panel lighting, photosensor, and control keyboard equipped with ten numeric keys and three control keys.

This keyboard has numeric keys for numeral input and functional controls, as well as control keys to work in association with the numeric keys. Numeric keys are labelled 0-9, and each numeric key will work with the control key to control one or more functions.

The control key is provided for direct control of the basic paging functions, for example, displaying a preceding piece of message, displaying a succeeding piece of message, and displaying a full page of message, etc. The control key acts in association with the numeric keys, to realise a dual-function for each numeric key in inputting of numbers and functional control. Besides, a certain parts or functions of the pager have been described in previous assertions, or similar to the pager described in previous assertions.

The overall operation of the pager is under the control of the CPU.

The CPU and memory, besides having the constituent means and stored programs as a regular design has, to control the general operational functions, also have various designs and structures as required by the invention, so as to ensure the realisation of the operations and controls of the pager according to with the invented method described above. The following is an example illustrating once more the operation procedure of the pager according to the invented MPOS in association with Fig. 7. As the.antenna picks up a call signal, the RF receiver demodulates the signal. The RF receiver comprises a demodulator means that demodulates the information code or enciphered information code and address code in the modulated signal. The RF receiver also has the function of stop receiving.In particular, the RF receiver has a control means that freezes the receiving operation on a temporarily basis, after the CPU receives a freeze command or after the pager receives the input of a code to enter a frozen state. In normal operations of the RF receiver, the demodulator first demodulates address signal, and sends the demodulated signal to a decoder for decoding, and thereafter check the address with the one stored in the address code storage means of the pager. If the addresses are identical, the receiver continues to demodulate the subsequent information code signal, and send it to the decoder for decoding. By means of a special decoding means in the decoder, this task may be accomplished.In a pager employing MPOS, the memory includes a storage means that stores a changeable personal password, a storage means that stores a changeable address, a storage means that stores a changeable decipher keyword, and storage means storing personal messages and public information.

The address on a pager adopting the invented MPOS in association with the MNKC is changeable by the owner. This function is performed through a special means in the CPU, namely, according to the correct procedure specified by the invented MNKC, an input new address code can replace (update) the old address stored in the memory. In particular, the CPU has a control means to update, according to a keyboard input, the stored data in said personal password storage means, address storage means, decipher keyword storage means. Therefore, the address code in the pager is changeable or assignable by the owner entering the code through numeric keys. The method of input is first a personal password is entered and checked. If the password is correct, then the requirement to change the address needs to be confirmed.If affirmative, a new address may be entered, and the pager henceforth uses this new address to receive calls. Or else the address is unchanged, and the pager continues to use the old address in receiving. If, however, the password is incorrect, a new password needs to be input again. If after n consecutive times (where n is integer greater than 1) the password thus entered are all wrong, the pager goes to the frozen state, and becomes functionally inoperative temporarily, and its functions may resume only after a "de-freeze" process. The "de-freeze" process begins with a personal password entering and checking. If correct, then the pager may be de-frozen and resume all functional operation. If incorrect, the password should be re-entered. If the passwords are incorrect for n consecutive times (where n is integer greater than 1), the pager then enters into a second class frozen state, and the pager can only be returned to a paging centre, to resume all functional operations by a special de-freezing equipment. By means of special means in the CPU, the input personal password is checked against the stored personal password in the memory, so as to control the pager in its execution of various normal functional operations (when the input password is correct), or else, the pager has its normal functional operation frozen in the way described above in this Description (as said in previous narrations, when the password is wrong for a consecutive times).

In addition, personal passwords can be changed through numeric keys. The changing process is that first the old password is entered. If the password is correct then a new password can be input which will take immediate effect. Thereafter, the password has been changed from the old to the new. If during the course of change, password is wrong, then old password has to be re-entered.

If, however, the password has been incorrect for a consecutive n times (where n is integer and greater than 1), the pager will enter a frozen state, and temporarily inoperative, and must go through a "de-frozen" process to recover the functional power. "De-freeze" process is stated in the above paragraph. By means of a special means in CPU, the required control function can be accomplished, which is to replace (update) the old personal password in the stored memory by inputting a new password, according to the dorrect operating steps of the invented method.In particular, CPU has a password checking means to check a keyboard-input personal password against the stored personal password, so as to control the pager to execute or to freeze its normal operations; a freezing means that decodes the frozen signal in signals received, and controls the pager to freeze the normal functions of the pager according to a decoded freeze command; and a means that controls the RF receiver, keyboard, display screen, and other input/output means to temporarily stop the functions of these of means under a frozen state.

The signals picked up by the decoder, are signals formed in POCSAG standard code and format, comprising 1 message bit, 20 information bits, 10 redundant check bits, and 1 even parity bit. Decoding program for the decoder is to utilise the 10 redundant check bit to check out and correct error bits (if any). The next task is to check the message bit. If it is "0", then the information bits represent an address, and the information bits are checked against pager's stored address. If identical, then the succeeding signals are to be decoded, otherwise the decoder notifies the CPU to shut off the RF receiver, pending suitable time to reopen the receiver.

If the message bit is "1", then the signal contains information codes, and the decoder sends the 20 bit decoded information to CPU.

Information received by a pager with numeric keys, can be coded in cipher (cryptograph) so that messages may be transmitted in secrecy. Even if a third person "intercepts" the message, he may not be able to understand the true information without a "decipher keyword". Therefore, in the CPU, a means is provided which can read any enciphered message coming in from the decoder, and which can decipher it by plugging in the decipher keyword stored in the memory.

Each pager model may have different "decipher keywords". The owner may input his own "decipher keyword" or change it, through the numeric keys, and then notifies the paging centre to encipher the messages according to the corresponding "encipher keyword", thus the transmission of information is kept in personal secrecy. The procedure for changing a decipher keyword is, first, a personal password is input for inspection. If correct, then the decipher keyword may be entered. After the new keyword is entered, under the control of a special control means provided in the CPU, the new keyword replaces (updates) the old decipher keyword stored in the memory, so that the new keyword takes effect immediately and with which the pager deciphers messages.In particular, the CPU provides a decipher means for deciphering cryptographed messages in the received signals by means of a stored decipher keyword. If the input personal password is wrong, the password should be re-entered. if it is wrong for n times (where n is integer greater than 1), the pager will enter the frozen state, rendering its functions inoperable, and the pager will resume functioning only after a "de-freeze" process, which has already been described above. The CPU has provided a special means for this purpose.

When the pager enters a state where its general functions have been frozen, i.e., its normal operating functions have been withheld, the pager will check any input personal password against the stored personal password. If the two are identical, the pager will resume normal operation. When the password is consecutively wrong for n times (where n is integer greater than 1), then the pager will enter a second class frozen state. At this time, all function should fail, and the pager can only be returned to the paging centre, and de-frozen by a specialised equipment, before the pager will resume operation.In particular, the CPU has a control means that, when the pager enters a state of normal operation functions being frozen, will check any input personal password against stored personal password, and will control the pager in resuming the function of normal operation, or entering another state where the pager needs to be de-frozen by the paging centre's equipment before resuming the functions of a normal operation.

In addition, in order to prevent message leak-out in case the pager is mislaid or not held in owner's hand, it necessitates a remote freezing function. This function sends out a freeze command to render a pager' 5 operations partly and temporarily ineffective.

The so call freeze command is a special command in the form of a message. When the pager is frozen, it will resume normal operation only after going through a "de-freeze" process. For this purpose, the CPU provides a special means, for decoding the freeze signal in the signals received, controlling the pager on the decoded freeze command, and withholding its normal operation functions, i.e.

rendering the pager to enter a frozen state.

As the CPU receives information codes, including all kinds of information (e.g. personal messages and public information), the bits are stored into memory, whereas the time information can meanwhile be extracted from the clock, and store it in memory.

Assuming the alarm mode is set as "beep", CPU invokes a loudspeaker which then gives out audio-alarm to alert the owner that a message is forthcoming. If alarm mode is set as "vibrate", the CPU sets off a vibrator which vibrates to alert the owner that a message is forth- coming. If the alarm mode is set as "quiet", CPU invokes neither the loudspeaker nor the'vibrator, but a pilot lamp blinks to alert the owner of a waiting call. During the period of alert, if any key is pressed, the alert will cease. If no key is pressed at all, the alert will also stop automatically after a predetermined period of time.

When the alert is issued, the message is not seen on the display screen, and instead, a request for "entering a password" is shown.

At this juncture, if the owner enters a correct password, the message does show up, or else the owner has to re-enter the password until it is correct. If the password is mistaken for more than n consecutive times (where n is an integer greater than 1), then the pager will enter the frozen state. The owner has to go through a "de-freeze" process to have the pager de-frozen.

Therefore, the CPU has a means for controlling the display screen so that no received messages will be displayed right away, under this secret mode of display protection, but the owner's entering of password is first prompted.

When the alert is press-stopped or auto-stopped, the message will remain displayed for a period of time, to allow sufficient time for the owner to read the message. If during message display, the photosensor detects a poor level of lighting, the CPU then invokes a penal light, to enhance message visibility to the owner even in a poor lighting environment. When the message display is complete, the CPU will cut off the panel light, and will display other information like time of the day, etc.

Information stored in the memory may be retrieved at any time, provided a key is pressed, and the information is displayed on a LCD screen. The information is stored in a last-in-first-out arrangement, i.e., the first retrieved piece of information is the last entered piece. After the first piece is retrieved, a next piece will continuously be displayed if the same key is pressed again, until keypressing stops. The the last retrieved piece remains on screen for a time period, then other information will be displayed.

On the pager which adapts to this invention, the numeric keys are used for information retrieval by direct entering the label number of the required message or information , and the last-in-first-out sequential display no longer applies. By pressing one of the ten numerics in association with the overleaf/enter key, functional selection of the required message is achieved according to the label digits, and this function is realised by the help of a special means in the CPU. In particular, the CPU provides a control means for storing the message consecutively into the storing means for personal messages and public information according to their labeled numbers, and displaying the message or information according to the control of numeric keys.That is to say, it is intended to first categorise and label the received data representative of various personal messages and public information according a predetermined classification, and to store them into memory through control; then to retrieved one specified piece of message and send it to screen display according to the numeric key control (as having already been described in association with Fig.1). Therefore the CPU has a further means for use to control keyboard; and to identify numeric inputs, selected functions and numeral digits, so as to realise all- said novel functions on a page-- adapted to the MNKC. Furthermore, before the time of message display, the owner is requested to enter password through numeric keys, which is checked for validity, to yield a result of keeping the confidentiality of the messages. In case of the entered password being mistaken for more than n consecutive times (where n is integer greater than 1), the pager will enter automatically a frozen state, in which its functions are withheld temporarily, and may not be resumed before going through a "de-freeze" process.

The above is merely an explanation of this invention by way of a number of concrete and preferred embodiments. However, this invention is in no way be confined to these embodiments. Persons skilled in the art may design various modifications or variations of this invention, based on the ideas and essence of the invention, but all of which may not go beyond the scope of this invention.

Claims (9)

1. A method for pager operation security (MPOS), said pager comprising both numeric keys and control keys, said method comprising the following steps: a. the owner of the pager selecting a predetermined paging functions by manipulating the numeric and control keys, rendering the pager to await the input of a personal password; b. the owner inputting, through manipulating the numeric keys, a predetermined numerical sequence representative of a personal password; c. the pager checking the validity of the input personal password; c-l. if valid, then pager performing selected function; c-2. if invalid, the pager awaiting further input of a password, and repeating the password cheching process, until all the passwords inputted for n consecutive times being invalid (where n being an integer greater than 1), then the pager entering a first frozen state; d. the owner selecting a de-freeze function, through maniputating the numeric keys and function keys, rendering the pager to await the input of a personal password; e. the owner inputting, through maniputating the numeric keys, a predetermined numerical sequence representative of a personal password; f. the pager checking the validity of the input personal password: f-l. if invalid, the pager awaiting further input of a password, and repeating the process of password checking until all the passwords inputted for n consecutive times being invalid (where n being an integer greater than 1), then the pager entering a second frozen state; f-2. if valid, the pager may be defrozen, and its operation may return to normalcy; g. the second frozen state being ended by means of the apparatus at the paging centre, to enable the pager to return to normalcy.

2. A method as claimed in Claim 1, characterized in said first frozen state referring to the frozen state in which regular functions of a pager becoming inoperable temporarily, but restorable after the pager performing a defreeze function under the direction of the owner.

3. A method as claimed in Claim 1, characterized in said second frozen state referring to the frozen state in which all functions of a pager becoming inoperable temporarily, and not defreezable by the owner alone, and defreezable only by means of the defreeze apparatus at the paging centre.

4. A method for pager operation security (MPOS), said pager compising numeric keys and control keys, said method comprising the following steps: a. the paging centre transmitting paging messages possibly including a predetermined freeze command, according to the owner's requirements; b. on receipt of a paging message, the pager identifying a freeze command and automatically entering a first frozen state; c. the owner selecting a defreeze function, through manipulating the numeric and function keys, rendering the pager to await a personal password; d. the owner inputting, through manipulating the numeric kayes, a predetermined numerical sequence representative of a personal password; e. the pager checking the validity of the input personal password: e-l. if invalid, the pager awaiting a further input of a password, and repeating the process of password checking until all the passwords inputted for n consecutive times being invalid (where n being an integer greater than 1), then the pager entering a second frozen state; e-2. if valid, the pager may be defrozen, and its operation may return to normalcy; f. the second frozen state being ended by means of a defreeze apparatus at the paging centre, to enable the pager to return to normalcy.

5. A method as claimed in Claim 4, characterized in said first frozen state referring to the frozen state in which regular functions of a pager becoming inoperable temporarily, but restorable after the pager performing a defreeze function under the direc-tion of the owner.

6. A method as claimed in Claim 4, characterized in said second frozen state referring to the frozen state in which all functions of a pager becoming inoperable temporarily, and not defreezable by the owner alone, and defreezable only by means of the defreeze apparatus at the paging centre.

7. A method as claimed in Claim 4, characterized in said preQetermined freeze command being a special coding of respective bits in the message codeword of the regular POCSAG paging format.

8. A pager adapted to the MPOS, said pager comprising: RF receiver, decoder; CPU, memory, display screen and control keyboard, characterised in: said control keyboard comprising numeric keys for numeric inputs and functional controls, and control keys for operation in association with numeric keys; said RF receiver comprising demodulating means for demodulating the information codes and address codes received in modulated signals, and control means for temporarily freezing all receiving functions of the RF receiver after the CPU having received a freeze command or after the pager having entered a frozen state upon receiving of input cipher keyword; said memory comprising storage means for a changeable personal password, storage means for a changeable address code, storage means for a changeable decipher keyword, and storage means for storing personal messages and public information; said CPU comprising a password checking means for checking the keyboard input personal password against the personal password stored in the memory so as to effect controlling the pager's execution or freezing its normal operation; a freezing means for decoding the freeze signal in the received signal, and for controlling the pager and freezing its normal operation according to the decoded freeze command; a controlling means for updating the stored data in said storage means for personal password according to keyboard input; a control means for, after the pager having entered a state, in which all normal operational function are frozen, checking the keyboard input personal password against the stored personal password, and controlling the pager in recovering its normal operation functions, or in recovering its normal operational functions only by means of the de-freeze apparatus at the paging center; a means for controlling the diaplay device not to instantly display at a display in secrecy mode but first request the owner to input passwords; and a means for controlling the RF receiver, keyboard display screen7 and other input/ouput devices to temporarily freeze their functional operation in a "frozen" state.

9. A pager adapted to MPOS as claimed in Claim 8 characterized in said control keys including an upshift key, a downshift key and an overleaf/enter key.