This International Standard specifies the requirements for the safety of nerve and muscle STIMULATORS@ defined in subclause 201.3.204@ for use in the practice of physical medicine@ hereinafter referred to as ME EQUIPMENT. This includes transcutaneous electrical nerve STIMULATORS (TENS) and electrical muscle STIMULATORS (EMS). NOTE A muscle STIMULATOR may also be known as a neuromuscular STIMULATOR. The following ME EQUIPMENT is excluded: ?C ME EQUIPMENT intended to be implanted or to be connected to implanted electrodes; ?C ME EQUIPMENT intended for the stimulation of the brain (e.g. electroconvulsive therapy ME EQUIPMENT); ?C ME EQUIPMENT intended for neurological research; ?C external cardiac pacemakers (see IEC 60601-2-31); ?C ME EQUIPMENT intended for averaged evoked potential diagnosis (see IEC 60601-2-40); ?C ME EQUIPMENT intended for electromyography (see IEC 60601-2-40); ?C ME EQUIPMENT intended for cardiac defibrillation (see IEC 60601-2-4).