Abstract: Methods are disclosed for performing cardholder verification associated with a customer card transaction through use of code sequences delivered independently to a point of sale terminal and to a customer unit (e.g., mobile phone). A point of sale terminal initiates a customer card transaction by sending a card number to a customer card processing system. An application server receives the card number and generates a code sequence corresponding to the transaction. The application server sends a first instance of the code sequence to the point of sale terminal and a second instance of the code sequence to the customer unit associated with the card number. Authorization status of the transaction is thereafter determined by an operator of the point of sale terminal comparing the first and second instances of the code sequence.

Abstract: The magnitude of a DC high voltage supplied to an internal element of a CRT is varied by a thermionic valve that is located within the envelope of the CRT and that forms a voltage divider with an external load resistor. Only a small scale signal referenced near ground is needed to produce a several thousand volt change in the high voltage supplied to the internal CRT element. The variable high voltage may control a variable deflection factor, variable spot size, or in the case of a beam penetration CRT, either variable persistence or variable trace color. In a particular beam penetration color CRT having a split anode the thermionic valve comprises a tetrode flood gun coupled by an electron mirror to a plate region in the neck of the CRT.