An apparatus and method for calculating and displaying local time for a plurality of cities in the world. The apparatus includes a memory for storing Greenwich mean time (GMT) information for each of the plurality of cities. The apparatus sets a reference time and counts the time that elapses from when the reference time is set. The apparatus calculates a local time of a city selected by a user, which is based on a difference between the GMT of the selected city and the GMT of a present location of the apparatus, the reference time and the counted elapsed time. The reference time may be either a time set by the user or a system time acquired from a signal generated from a remote system.
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1. An apparatus for displaying local time information, comprising:
- means for storing Greenwich mean time (GMT) information for each of a plurality of cities;
- means for receiving a reference time from a signal received from a remote system;
- means for counting a duration of time that elapses from when said reference time is acquired;
- means for selecting at least one of said plurality of cities and automatically calculating a local time of said selected city, said local time being based on a difference between the GMT of said selected city and the GMT of a present location of said apparatus, said reference time and said elapsed time; and
- means for outputting said local time.
2. The apparatus of claim 1, wherein said apparatus is a mobile telephone.
3. The apparatus of claim 2, wherein said reference time is a system time acquired from a sync channel message received by said mobile cellular phone from a base station of a CDMA (Code Division Multiple Access) cellular system.
4. In an apparatus having a display and a memory for storing Greenwich mean time (GMT) information for each of a plurality of cities, a method for generating local time information, comprising the steps of:
- receiving a reference time from a signal received from a remote system;
- counting a time which elapses from said acquiring of said reference time;
- selecting at least one of said plurality of cities;
- automatically calculating a local time of said selected city based on the difference between the GMT of said selected city and the GMT of a present location of said apparatus, said reference time and said elapsed time; and
- displaying said calculated local time.
5. The method of claim 4, further comprising the step of displaying a message to set a reference time if said step of setting a reference time does not occur.
6. The method of claim 4, wherein said step of selecting includes the substeps of:
- displaying a list of said plurality of cities; and
- scrolling through said list to select a desired one of said plurality of cities.
7. The method of claim 4, wherein said apparatus is a mobile telephone.
8. The method of claim 7, wherein said reference time is a system time acquired from a sync channel message received from a base station of a CDMA cellular system.