| 摘要 |
Telephone calls are routed by means of a routing device which prefixes user generated call numbers with a prefix code which determines a network connection route and provides billing and customer identification information. The device determines the preferred route by addressing a look up table (134, 135) which is periodically updated with updating information transmitted via radio broadcast from a control centre. The device may be a stand alone device connected intermediate a telephone and a local exchange connection or may be formed unitarily with a telephone, facsimile machine or mobile telephone. The broadcast updating information is transmitted by a message pager transmitting system during off peak message handling times. The device is provided with two memory areas for first and second look up tables (134, 135) so that one of the tables remains addressable while the other one of the tables is being updated with updating information, the most recently updated table being subsequently used as a decision table.
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