Abstract: Apparatus is provided for converting serial bit digital signals of selected line rate from a plurality of sources into a single serial bit signal for time division multiplexing (TDM) in periodic frames by a central receiver, in a system in which each source is responsive to command signals for transmitting signal information to the receiver.

Abstract: Telephone system interface circuitry for regulating the full duplex exchange of asynchronous serial bit signal information between the system's station equipment and central equipment matrix switch includes a central equipment signal processor, central equipment master clock, and individual central equipment signal ports for each station, and includes in each station equipment variable time delay transmission circuitry responsive to the signal information transmitted periodically from the central equipment for transmitting station information at the same periodic interval but delayed from the received central signal information by a delay time interval selected to regulate the actual time of arrival (TOA) of the station information at the associated central port coincident with a desired TOA for that port.

Abstract: A process for forming credit cards in which encoded information is screen printed on a plastic sheet. In the process, a photographic film is placed in contact with a surface having film exposure means positioned with respect to the surface. Locating means are formed on the film and the film is positioned on the surface through the locating means. Thereafter, small predetermined coded spaces are exposed on the film and the exposed film is developed to provide coded darkened spaces corresponding to the exposed coded spaces.The developed film is placed against a silk screen having first positioning means which coact with the locating means on the film to position the film with respect to the silk screen. The screen is coated with a light-sensitive emulsion and light is shone on the screen through the film to expose the emulsion except at the coded darkened areas.The screen is washed to provide a coded screen having openings corresponding to the exposed coded spaces on the film.

Abstract: Method for marking a large number of credit cards with unique credit card numbers. A lot size of plastic sheets is selected which is related to the numerical base, b, for expressing the sheet numbers. Each sheet is identically marked with position numbers placed in each of a plurality of uniform credit card areas on each sheet with each area having a position number differing from the position numbers of the other areas on the sheet. Each sheet in the lot is marked with an individual sheet number with sheet numbers being marked by separately marking the individual digits making up the sheet number. After marking the sheets with a digit in the sheet number, the sheets are sorted before marking the next digit. The sorting size is dependent upon the numerical base, b, and the order of the digit which has been marked. After sorting, the sheets in each of the sorted groups have the same distribution of sheet numbers. The next digit is then marked on the sheets and the sheets are again sorted, etc.