Abstract: A communications adaptor for a remote action terminal connected to a telephone line in parallel with a telephone set in order to interchange remote action data with at least one server via the telephone line and a remote action network to which the server is connected, the data being interchanged using a frequency band different from that used by the signals relating to the telephone set, the adaptor including a binary data transmitter/receiver operating by frequency shift keying between two frequencies and the remote action network likewise including a binary data transmitter/receiver operating by frequency shift keying between the same two frequencies, dialog taking place in alternation between the transmitter/receivers by interchange of signals. The adaptor also includes a remote signalling device provided with means for causing signalling to be transmitted by the adaptor indicating that an absence of dialog has been observed for longer than a predetermined period of time.

Abstract: A power supply switchover device is provided for electrical apparatus such as teleaction terminal equipment. A switching circuit puts a storage battery into and out of use by connecting it to at least one supply terminal of the electrical apparatus to which another source is also connected. A control circuit causes the switching circuit to connect the storage battery when the supply terminal falls to a predetermined potential as furnished by the power supply, and a blocking circuit acts on the control circuit to initiate disconnection of the storage battery, when and as long as said terminal is at a potential that is lower than a determined threshold value.

Abstract: Low-level, wide-band signals e.g. for use in telephone transmission are switched in a matrix device. The overall matrix is subdivided into elementary matrices of smaller size and each inlet of the overall matrix is provided with a selector for selecting the appropriate elementary matrix which contains the desired cross-point. This subdivision is performed as is conventional to reduce interference and attenuation from echos generated in the unused portions of the matrix, but it has the drawback of increasing the complexity of switch control, two selectors and one cross-point needing activation in the place of a single cross-point. The present invention provides selectors which are sensitive to the conductive state of the cross-points to which they are directly connected to repeat the conductive condition to their respective inlet of the overall matrix, thereby simplifying switching control without sacrificing transmission characteristics.