A method and system for providing electronic wireless credit card transactions to small businesses in conditions where the wireless telecommunications network is old and/or underdeveloped. The system allows a merchant to accept payment cards firstly via TCP/IP and secondly via SMS and/or USSD wherever only the most basic GSM network is available. The merchant does not need dedicated wireless terminals to do that. With the smartphone app and the peripheral card reader using the novel method, a merchant in the middle of a remote African village or Siberia can accept a payment cards on the spot, right there and then, if basic GSM network is available, but can also use the same devices in e.g. central London with 4G networks. A corresponding software product is also described.