The invention concerns novel ionic compounds with low melting point whereof the onium type cation having at least a heteroatom such as N, O, S or P bearing the positive charge and whereof the anion includes, wholly or partially, at least an ion imidide such as N\u2212 wherein X1 and X2 are identical or different and comprise SO or PF, and their use as solvent in electrochemical devices. A transmitter-receiver transmits the report information generated by the center control unit to a user terminal. An electrical current is introduced to pass along the strip between the ends. when receiving the sub-bitstreams from the respective terminals, the MCU combines the sub-bitstreams into a composite bitstream and sends the composite bitstream to a display terminal; D.