Title:
PREPAID DATA COMMUNICATION SYSTEM
Document Type and Number:
Japanese Patent JPH0215739
Kind Code:
A
Abstract:
PURPOSE: To form a speech system in resistance even to an illegal action by comparing verification information generated by a verifying module with verification information generated from a terminal equipment in the continuity of speech. CONSTITUTION: When a user picks up a receiver 124 of a telephone set, a verifying module 108 receives an off-hook signal DT, and generates a random number being an initial verification value Ko. When the telephone set receives a verification signal corresponding to the value Ko, and receives a charge signal, only a sum corresponding to charge to be paid is subtracted from a valid balance in the memory of a card by a reader. When a new charge signal is transmitted in speech, the telephone set subtracts a new speech sum from the card, calculates a new verification value K'2 , and transmits it to the verifying module 108. At the same time, the verifying module 108 calculates a new verification K2 , and compares it with the received K'2 . Thus, a speech system can actually fulfill a condition necessary for safety guarantee.
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Inventors:
KUROODO BARUROO
KURISUCHIYAN GIYUION
JIYAN RUU POWARO
KURISUCHIYAN GIYUION
JIYAN RUU POWARO
Application Number:
JP7635989A
Publication Date:
January 19, 1990
Filing Date:
March 28, 1989
Export Citation:
Assignee:
SCHLUMBERGER IND SA
International Classes:
H04M15/28; G07F7/00; G07F7/02; G07F7/08; H04M17/00; H04M17/02; (IPC1-7): H04L11/02; H04L12/14; H04M15/28; H04M17/00
Attorney, Agent or Firm:
Minoru Nakamura (7 outside)
Next Patent: DATA COLLECTING SYSTEM BY RADIO COMMUNICATION