Mobile unit and a method for enabling a dial lock in the mobile unit

• US 5,646,604 A
• Filed: 01/26/1995
• Issued: 07/08/1997
• Est. Priority Date: 06/30/1994
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Maruyama, Minoru, Fujiwara, Shuuji
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WILSON JR, WILLIAM HALL
• Application Number:
  US08/378,397
• Time in Patent Office: 894 Days
• Field of Search: 340/825.31, 340/825.34, 340/825.5, 340/825.56, 340/825.44, 340/825.47, 340/311.1, 379/58-63, 379/91, 380/4, 380/23, 380/25, 380/30, 455/33.1, 455/54.2, 455/89
• US Class Current: 340/5.22
• CPC Class Codes: H04M 1/673 the user being required to key in a code
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones

Abstract

A mobile unit having a unit for transmitting and receiving signals to and from a base station by radio telephony, an input unit for use in entering information, a display and a control unit, is provided with a first memory in which "unwritten" or "written" is stored as a state of a password for enabling the dial lock, and a second memory in which a password for enabling the dial lock is stored. When a dial lock signal is supplied from the input unit, the control unit writes a password entered at the input unit in the second memory and changes the state of a password in the first memory from "unwritten" to "written." Thereafter, except after providing the password, the mobile unit cannot be used for calling. Moreover, the password cannot be modified.

Claims

1. A mobile unit for achieving radio transmission and reception relative to a base station, comprising:

means for transmitting and receiving signals to and from said base station by radio telephony;

user input means for use by a user in entering information and in entering a dial lock signal;

display means;

a first memory in which "unwritten" or "written" is stored as a state of a password set for dial lock prevention of unauthorized use of said mobile unit;

a second memory in which a password from said dial lock signal and set for dial lock preventing unauthorized use of said mobile unit, is stored; and

control means for controlling said transmitter and receiver means and said display means, for determining whether said dial lock signal is supplied from said input means, and when it is determined that said dial lock signal is supplied, for writing a password entered by said user at said input means into said second memory, and for changing the state of a password in said first memory from "unwritten" to "written".

2. A mobile unit according to claim 1, wherein only when said state of a password in said first memory is "unwritten," said control means enables dial lock which prevent unauthorized use in response to said dial lock signal supplied from said input means;

and when said state of a password in said first memory is "written," said control means does not validate dial lock in response to said dial lock signal supplied from said input means.

3. A mobile unit according to claim 1, further comprising means for connecting a ROM writer that allows said control means to modify the dial lock password.

4. A mobile unit according to claim 3, wherein said control means determines whether said ROM writer connected via said connecting means is authorized.

5. A mobile unit according to claim 1, further comprising a third memory, in which a frequency of transmission and reception that is allowed with dial lock disabled, is stored,

wherein when the frequency of transmission and reception performed with dial lock disabled exceeds the allowed number of transmissions and receptions in said third memory, said control means changes said state of a password in said first memory from "unwritten" to "written" and writes in said second memory a password meaning that dial lock is disabled.

6. A method for enabling a dial lock to prevent unauthorized use of a mobile unit having a transmitter receiver means, user input means, display means, a first memory in which "unwritten" or "written" is stored as a state of a password for enabling the dial lock, a second memory in which a password for enabling the dial lock is stored, and control means, comprising the steps of:

when said state of a password for enabling the dial lock, which resides in said first memory, is "unwritten" and a dial lock signal is supplied by a user from said user input means, storing a password included in said dial lock signal entered by said user at said input means in said second memory; and

changing said state of a password in said first memory from "unwritten" to "written".

7. A method for enabling a dial lock to prevent unauthorized use of a mobile unit having a transmitter receiver means, user input means, display means, a first memory in which "unwritten" or "written" is stored as a state of a password for enabling the dial lock, a second memory in which a password set for enabling the dial lock is stored, and control means, comprising the steps of:

when said state of writing a password set for enabling the dial lock, which resides in said first memory, is "unwritten" and a dial lock signal is supplied by a user from said user input means, determining whether a first password entered at said input means agrees with a second password included in said dial lock signal;

when these two passwords agree with each other, storing the password value in said second memory; and

changing said state of a password in said first memory from "unwritten" to "written".

8. A method for enabling a dial lock of a mobile unit for a mobile unit having a transmitter receiver means, user input means, a display means, a first memory in which "unwritten" or "written" is stored as a state of a password for enabling the dial lock, a second memory in which a password set for enabling the dial lock is stored, and a control means, comprising steps of:

when said state of a password for enabling the dial lock, which resides in said first memory, is "unwritten" and a password is to be stored in said second memory with no dial lock signal supplied from said input means, storing in said second memory a password meaning that dial lock is disabled; and

changing said state of the password in said first memory from "unwritten" to "written."

9. A method for enabling a dial lock of a mobile unit for a mobile unit having a transmitter receiver means, user input means, a display means, a first memory in which "unwritten" or "written" is stored as a state of writing a password set for enabling the dial lock, a second memory in which a password set for enabling the dial lock is stored, and a control means, comprising steps of:

when said state of a password for enabling the dial lock, which resides in said first memory, is "unwritten" and it is determined that the number of transmissions and receptions performed by said mobile unit exceeds the number of transmissions and receptions enabled in a third memory, storing in said second memory a password meaning that dial lock is disabled; and

changing said state of a password in said first memory from "unwritten" to "written."

10. A method for enabling a dial lock of a mobile unit for a mobile unit having a transmitter receiver means, user input means, a display means, a first memory in which "unwritten" or "written" is stored as a state of a password for enabling the dial lock, a second memory in which a password for enabling the dial lock is stored, and a control means, comprising steps of:

connecting said mobile unit to an external ROM writer;

allowing said mobile unit to execute an operation on a password residing in said second memory and transmit a resultant coded password to said ROM writer;

allowing said ROM writer to execute an inverse operation on a received coded password and transmit a resultant password to said mobile unit;

allowing said mobile unit to compare said password residing in said second memory with said password received from said ROM writer and thus determine whether said ROM writer is authorized; and

when it is determined that said ROM writer is authorized, changing the contents of said first memory from "written" to "unwritten."