A worldwide television tuning system is configurable to the television
standards and channel frequencies of multiple different countries based
on a country's ITU long-distance country code. The tuning system
maintains a country code table listing a plurality of countries according
to their ITU codes. The tuning system also maintains multiple
channel-to-frequency mapping tables that correlate channel numbers to
corresponding frequencies for associated countries in the country table.
The country table indexes the channel-to-frequency mapping tables. During
configuration, a user or application selects a particular country by
passing in the ITU code. The tuning system uses the ITU code to locate an
entry for that country in the country code table. The table entry
contains an index to an associated channel-to-frequency mapping table for
the selected country. The tuning system loads and saves the
channel-to-frequency mapping table for subsequent use. The
channel-to-frequency table also identifies the appropriate television
standard for the selected country. During tuning, the user or application
enters a particular channel number. The tuning system uses the channel
number to lookup a corresponding television frequency in the
channel-to-frequency table. The tuning system then tunes to the
television frequency. The tuning system stores a set of tuning
frequencies for corresponding channels within a particular locale. If the
tuning system is transported to another locale and then back to the
original locale, the tuning frequencies may be retrieved from memory to
restore operation within the original locale, rather than having to
reconfigure the system.