Abstract: A credit card status verification system is disclosed in which the status of very large numbers of credit cards is contained and accessed from a compact storage media, such as a CD-ROM disk, at a remote location, thereby eliminating the necessity of obtaining the status information from a centrally located facility via a communication link. A data mapping algorithm is employed to map credit card numbers to status containing locations within memory without requiring large amounts of memory space for addressing. A multiple level screening process is employed for checking the validity of a credit card number and the credit status of a credit card which is both quick and economical.

Abstract: A pair of interface devices, mounted externally to a pair of residential telephones, can place a temporary hold on the associated telephone line circuit. Each interface device interconnects a standard residential telephone with an associated telephone line circuit. In a two telephone arrangement to place the telephone circuit in a hold condition, the user throws a switch mounted on the interface device, and hangs up the handset (goes on hook). The switch places two indicator lamps across the two-wire line circuit to simulate an off-hook condition. To remove the hold condition, the user merely throws the same switch or the switch associated with one of the other phones in the residence. There is no need to return to the original phone first used to establish the hold.