1. IN A POLAR ADAPTER FOR CONNECTING A PRINTING TELEGRAPH INSTRUMENT OF THE MAKE-BREAK TYPE TO A POLAR TELEGRAPH LINE HAVING SIGNAL CONDUCTORS WHEREIN DIAL SWITCHING AND FUNCTION SIGNALS AS WELL AS INTELLIGENCE SIGNALS ARE TRANSMITTED ON THE LINE, MEANS FOR CODE CONVERSION AND SIGNAL SHAPING, COMPRISING MEANS TO PRODUCE A CONTINUOUS SERIES OF ACCURATELY TIMED PROBE PULSES, SECOND MULTIVIBRATOR MEANS CONNECTED TO AND TRIGGERABLE BY SAID FIRST MULTIVIBRATOR MEANS TO PRODUCE A SHAPED BIMODAL OUTPUT, INHIBITING VOLTAGE SUPPLYING MEANS FOR THE SAID SECOND MULTIVIBRATOR MEANS COMPRISING AN ELECTRICAL CLAMP CIRCUIT, CONNECTED TO THE SAID SECOND MULTIVIBRATOR MEANS AND EFFECTIVE TO PREVENT THE TRIGGERING THEREOF BY SAID FIRST MULTIVIBRATOR MEANS DURING THE APPLICATION OF INHIBITING VOLTAGE THERETO, AND DISCHARGE MEANS CONNECTED TO SAID INHIBITING VOLTAGE APPLYING MEANS EFFECTIVE TO DISCHARGE THE INHIBITING VOLTAGE THEREOF WITHIN A PREDETERMINED PERIOD OF TIME DURING WHICH THE SAID ACCURATELY TIMED PROBE PULSES ARE RENDERED INEFFECTIVE TO TRIGGER THE SAID SECOND MULTIVIBRATOR MEANS, THE SAID DISCHARGE MEANS BEING CONNECTED TO AND THE OPERATION THEREOF INITIATED BY THE VOLTAGE OF A TELEGRAPH SIGNAL CONDUCTOR AND COMPRISING AN R.C. CIRCUIT.