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: - ME EQUIPMENT intended to be implanted or to be connected to implanted electrodes; - ME EQUIPMENT intended for the stimulation of the brain (e.g. electroconvulsive therapy ME EQUIPMENT); - ME EQUIPMENT intended for neurological research; - external cardiac pacemakers (see IEC 60601-2-31); - ME EQUIPMENT intended for averaged evoked potential diagnosis (see IEC 60601-2-40); - ME EQUIPMENT intended for electromyography (see IEC 60601-2-40); - ME EQUIPMENT intended for cardiac defibrillation (see IEC 60601-2-4).