Abstract: A system which enables the titles of recordings to be selected from storage media containing a number of titles and held in a magazine, in particular the titles of CDs housed in a number of CD boxes. The storage media include a list of the recording titles they contain. Also called for is a player for the recordings. The system includes a device, forming part of the recording player, which enables titles selected from any of the storage media to be played; a decoding device, forming part of the recording player, which converts keyed-in code numbers into title selections; a light pen, connectable to the player, for reading bar codes, with the bar codes thus read being fed to the decoder; and a compilation, separate from the storage media and recording player, of bar codes, each of which corresponds to one of the stored titles of the recordings and can be read by the light pen.

Abstract: For the measurement of the diameter of coins (1) or other circular objects, such coins or other objects pass the guide channel at substantially the same velocity. In a lateral wall of the guide channel, at least two photoelectric detectors (3, 4) are arranged at different heights which are obscured by such coins or other circular objects when passing the channel (FIG. 1 ).

Abstract: For detecting a foreign body, as, for instance, a thread (3) or a wire in a coin channel (10) or for the recognition of the edge outline of coins moving along the guide channel, a photoelectric detector (1, 2) monitors the coin channel (10) (FIG. 1).

Abstract: A testing device for bank notes, or similar instruments of payment in sheet form for automatic vending machines, has a testing channel (20) with a transport device (7) and scanning devices for recognizing and checking the authenticity of the bank note (3). An input channel (2) of variable width is in front of the testing channel (20). The input channel (2) includes two channel halves (21), one on either side of the longitudinal center axis (22) of the input channel (2). The two channel halves (21) can be adjusted synchronously against the force of a spring. In their contact position, the channel halves (21) determine the minimum width of the channel, and in their separated end position they determine the maximum width. A bank note (3) of any type is introduced into the input channel (2) at its locked maximum channel width as far as a passage detector (19) arranged in a starting region of the testing channel (20).

Abstract: A circuit for controlling the frequency of a pulse generator associated with a microprocessor that is connected to power line frequency, uses an RC-stage which is connected ahead of the pulse generator as the frequency-determining element and which has a resistor 19 that is variable by a control signal derived from the microprocessor. The control signal is obtained by comparing the power line frequency and the pulse frequency with one another.