초록 ▼

An apparatus and a method of providing an access control for transmitted stock market data from a central radio station to a plurality of one-way radio receivers. Into each receiver is inputted an access code including a cypher pointer which provides for scrambling of the remainder of the access cod

An apparatus and a method of providing an access control for transmitted stock market data from a central radio station to a plurality of one-way radio receivers. Into each receiver is inputted an access code including a cypher pointer which provides for scrambling of the remainder of the access code which includes the authorized services, the service cutoff date, and the unit serial number which is unique to a particular receiver. The cypher pointer is used to rotate a common map in the receiver used for unscrambling and in the central station used for scrambling. In order to receive service, the permanently stored serial number of the unit must compare with the serial number of the access code, the cutoff date must be greater than the present system date transmitted from the central station, and there must be an authorized service class.

대표청구항 ▼

An access control system for transmitting data from a central station to a plurality of receiving stations each of said receiving stations each of said receiving stations comprising: first memory means for permanently storing a unique serial number; second temporary memory means for storing a manual

An access control system for transmitting data from a central station to a plurality of receiving stations each of said receiving stations each of said receiving stations comprising: first memory means for permanently storing a unique serial number; second temporary memory means for storing a manually inputted access code including in scrambled form said serial number and a service cutoff and also including a cypher pointer which is not scrambled; map means responsive to said cypher pointer for unscrambling said scrambled serial number and cutoff date; and means for comparing said unscrambled serial number with said permanently stored serial number for validating said receiving station to allow such station to receive said transmitted data.