The cards in circulation in Nigeria are with electronic chips, but before 1994 magnetic cards produced by the Swiss company Autelca were used. During the first period, standard test-type cards, utilized in other countries too, were supplied and used by the public. The Nigerian ones can be easily recognized, however, because the serial number has no prefix, but the first two numbers, 20 or 40, indicate the corresponding value in Naira, the local currency.
