To allow a management device managing each public telephone set to quickly discriminate whether or not received data from a public telephone set are re-transmission data in the case of communication between the public telephone sets.
When a public telephone set 1 transmits a plurality of notice data denoting a utilizing state of the like of itself to a management device 4, the public telephone set 1 transmits time data at the transmission of the notice data with the notice data, and when the public telephone set 1 cannot receive a confirmation mobile station from the management device at the transmission of each of data, the public telephone set 1 transmits again the transmitted notice data and time data together with a re-flag, the management device has a data area 43A1 and a time area 43A2 respectively storing the notice data and the time data from the public telephone set 1 and when the management device receives the re-transmission flag from the public telephone set 1, the management device compares the received time data with the time data of the time area together with the re-transmission flag and discriminates the received notice data as the re-transmission data when both the data are coincident.
| JP2006279978 | MOBILE TELEPHONE WITH BUILT-IN CHARGE ACCOUNTING FUNCTION |
| JPH04220058 | COMMUNICATION EQUIPMENT |
| WO/1998/018251 | PAYMENT SCHEME FOR A MOBILE COMMUNICATION SERVICE |
EDA SHIGEHIRO
YOSHIMURA KATSUMI
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