information to the device then invert the 34 on 34 state for accepting information or for measuring the temperature of the cells the multiplexing transistor once again permits the intelligent device to employ the 34 t 34 terminal as a data bus providing in this way an intelligent supply battery or an non intelligent supply battery if no data exchange is necessary the switching transistor 32 39 is shown outside the microregister so as to clearly illustrate the principle to reduce costs it may be incorporated within the microregister or the asic circuit the choice of the series or parallel operation of the multiplexing transistor switch is decided in accordance with the implicit state of this transistor its resistance in the 34 on 34 state the variation in the resistance of the thermistor and other specifications of the circuit configuration clearly it may be possible to put the invention into practice by the use of different basic circuits however so long as the circuit is capable of identifying the type of the device for which the supply battery is intended the supply battery will be capable of operating in the required manner the microprocessor may be combined with devices other than a transistor in order to facilitate the practice of the invention the outer case of the supply battery may be different from that described and shown so long as the three terminals are employed the same case will however be employed for both intelligent devices and non intelligent devices in the presently described invention the case is shown to have three terminals it will be clear that this number is a minimum condition there may be embodiments in which further terminals are.