Abstract: Subscribers (Ab1 to Ab8) in a telecommunications system are normally connected via respective subscriber lines (L1 to L8) to respective subscriber terminals (T1 to T8). Automatic subscriber line test means are connected via a subscriber line test bus (BL) and various relay contacts (r1 to r8 and re1 to re8) to the subscriber lines for testing purposes. Eight subscriber terminals (T1 to T8) populate a single circuit card, thereby constituting a terminal unit (TU1 to TUp). A group of terminal units is associated with a spare terminal unit (TUS). When a faulty terminal unit is detected, it is taken out of service and the spare terminal unit takes over. This is done by switching the subscriber lines connected to the faulty terminal unit over to the test bus. The spare terminal unit is likewise connected to the test bus. To enable the test means to continue testing the remainder of the telecommunications system without being interrupted by the emergency connection via the test bus, isolator means (I) are provided.

Abstract: The invention relates to a method of controlling the heating of a chamber and to a controlled installation for heating a chamber. Circulation of a heat-conveying fluid between a solar energy collector (CS) and a water heater chamber (10) is stopped when the temperature t.sub.A of a sensor placed at the outlet of the collector is lower than the temperature t.sub.B of a sensor placed at the inlet of the heat exchanger of the water heater, and also when the temperature t.sub.B is lower than or equal to the temperature t.sub.C of a sensor placed at the outlet of the heat exchanger. Application to producing domestic hot water.

Abstract: The invention relates to an automatic switching arrangement for two batteries which are charged in parallel and discharged in series. The arrangement includes a control unit and a charging circuit; the control unit is a circuit which includes a transistor (T1), a resistor (R1) and a diode (D1) which is connected between two terminals of opposite polarities of the batteries (BT1) and (BT2), the transistor being blocked or conductive according to the direction of the voltage at the terminals of the diode; the transistor controls switching units (T2,T3) of the charging circuit. A switch (CT4, Th, CT11) can be disposed in series with the diode (D1). Application to stand-by batteries.

Abstract: Circulation of a heat-conveying fluid between a solar energy collector (CS) and a water heater chamber (10) is stopped when the temperature t.sub.A of a sensor placed at the outlet of the collector is lower than a temperature t.sub.B +Dt, where the temperature t.sub.B is that of a sensor placed at the inlet to the heat exchanger of the water heater, where a temperature t.sub.C is that of a sensor placed at the outlet of the heat exchanger, and Dt is a temperature offset which increases with a decrease in the temperature difference t.sub.B -t.sub.C.

Abstract: An aleatory source of energy, e.g., a battery of photocells (1), supplies energy to a load (5) and to a storage battery (3). When the source is supplying more energy than is being drawn by the load, the storage battery is charged; when the source is supplying less than the demand, the shortfall is made up by drawing energy from the storage battery. The state of charge of the storage battery is monitored by a meter (8) which governs a regulator (7). Once the battery is charged to a predetermined threshold, the amount of current it draws from the source is regulated, and energy supplied by the source in excess of the combined requirements of the load and of battery charging is diverted to a storage means (6) other than the storage battery (e.g., a mains electricity supply grid). The flows of energy to both the battery and the other storage means are controlled by the regulator (7) as a function of the state of charge of the battery.