Abstract: The invention relates to a switching network for a communication system, comprising m/1 stages and in which cells are transmitted in accordance with a time-division multiple access method and the switching is effected on the basis of the routing information contained in the header. The arriving cells are temporarily stored in a buffer until a free frame is available. The queues built up in the buffers of the m/1 stages are to be processed in the most fair manner. For this purpose it is proposed to assign a memory to each m/1 stage of each auxiliary line (Zl . . . Zm), to which memory are applied the results of the comparisons between routing information and address of the trunk line (A) and to determine for the decision circuits the order in which the cells stored in the buffers (B) are read out.

Abstract: The invention relates to an optical wavelength multiplexing and/or demultiplexing device. The device comprises a digital phase grating having at least four steps. The grating diffracts light of at least three different wavelengths in different central diffraction orders. Since the grating period may be high in comparison with the wavelengths light-emitting diodes may be used as light sources.

Abstract: An optical power divider for use with one incoming and a plurality of outgoing glass fibers includes an imaging device arranged on an optical axis between the incoming and outgoing glass fibers. At least one plane binary phase grating is disposed in the pupil of the imaging device. The grating is one-dimensional, has a duty factor of at least substantially 1:1, and has an optical path difference of at least substantiallyH=0.32.lambda.+n.lambda.or H'=0.5.lambda.+n.lambda.where n=0,1,2 . . . . The end of the incoming glass fiber is coaxial with the optical axis. The outgoing glass fibers are arranged in such a way that they receive the radiation which has been diffracted into the various diffraction orders of the phase grating. .lambda. is the wavelength of the radiation.

Abstract: Method the transmission of data packets in a TDM transmission loop wherein the frame is subdivided into several groups each having the same number of words, and each group comprises either exclusively narrow-band channels for the transmission of speech data or is associated with the high-rate channel for groups comprising narrow-band channels always comprises an unambiguous bit sample of, for example, the highest priority is assigned to each group. When a subscriber station wants access to a word group in the high-rate channel it transmits its own identifying bit sample and possibly priority data in a signaling word. When this bit sample is returned through the loop undisturbed the subscriber station immediately accesses the assigned group of words in the high-rate channel for the transmission of a data packet. Allocation of channel access among individual subscriber stations is prioritized.

Abstract: The record carrier according to the invention comprises a substrate on which an electrode is provided which, on the side remote from the substrate, has a low-ohmic photoconductive layer which is covered with a second transparent electrode which is provided wihh a thermoplastic layer. For storing information the electrodes are connected to a voltage source and the thermoplastic layer is charged electrostatically and exposed in known manner. Upon exposure of an area of the thermoplastic layer, the light will fall through the transparent electrode on the low-ohmic photoconductive layer. As a result of the current passage, Joulean heat is produced which heats the thermoplastic layer in the place of the exposed area and softens it thereby deforming the layer by electrostatic forces in accordance with the charge.The thermoplastic layer may, in known manner, also have photoconductive properties or be provided with a further photoconductive layer.

Abstract: A device for coupling a first optical signal of a first wavelength into a transmission glass-fiber and for coupling a second optical signal, which has a second wavelength which differs from the first wavelength, out of the fiber. The two signals travel in the transmission glass-fiber in opposite directions. The optical signals also travel in other, spatially separated glass fibers. The device includes an imaging device arranged between the transmission glass-fiber and the other glass fibers. In the pupil of the imaging device, a binary optical grating is disposed. Other glass fibers receive the second optical signals which have been diffracted into the diffractions orders of the grating.The grating is a phase grating and is arranged on an optical axis of the imaging device. It has a duty factor of at least substantially 1:1 as well as an optical path difference, H=(n-1)h, which is substantially(N-1)h=n.sub.1 .lambda..sub.I, where n.sub.1 =1, 2, 3, . . .and(N-1)h=(m.sub.1 +1/2).lambda..sub.k where m.sub.