Defines electrical input and output characteristics of intrinsically safe transmitting and receiving circuits forming a low speed digital data transmission link in which data is transmitted using current loop techniques.Cross References:BS 229BS 1259BS 1442BS 4683BS 5501:Part 7BS 5501:Part 9BS 5754BS 6556:Part 2BS 6556:Part 3Mines and Quarries Act, 1954Health and Safety at Work etc. Act 1974