Title:
PREPAID CARD PUBLIC TELEPHONE SET
Document Type and Number:
Japanese Patent JP2674491
Kind Code:
B2
Abstract:
PURPOSE: To reject communication utilization by a prepaid card which disturbs the update process of a valid call rate and reject the card from a public telephone set into which the card is inserted by wiring dummy data on the inserted prepaid card and reading them, and detecting the writing process not being disturbed.
CONSTITUTION: A data writing confirmation control part 9 controls a prepaid card control part 5 to add one to a read-in valid call rate D0, writes the result as the dummy data D1 on the prepaid card, and then reads dummy data D1' out. If the data can not be read or if the read value D1' is different from the written value D1, it is judged that the prepaid card is illegal, the communication utilization is rejected, and the card is discharged. When the data read out of the prepaid card match the written value, the prepaid card is judged as a legal card; and the original valid call rate D0 obtained by subtracting one from the data D1 is sent to an exchange through a control part 4 and connection as an ordinary prepaid card public telephone set and the update processing of the valid call rate are performed.
Inventors:
Kazuhiko Nakamura
Application Number:
JP31946993A
Publication Date:
November 12, 1997
Filing Date:
December 20, 1993
Export Citation:
Assignee:
NEC
International Classes:
H04M17/00; (IPC1-7): H04M17/00
Attorney, Agent or Firm:
Wakabayashi Tadashi
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