The invention relates generally to the processing of electronic payments that involve an payment instrument. A payment instrument reading device is paired with a payment initiating device to allow transaction information generated by the payment initiating device to be automatically transmitted to its associated payment instrument reading device. This means that rekeying of transaction information is not required. In some embodiments one or more beacons are provided in a premises, to allow the location of a mobile payment initiating device to be determined. This location is used to either direct the payment initiating device to a payment instrument reading device, or vice versa. Transaction data generated by the payment initiating device is automatically transmitted to the payment instrument reading device. A pairing module is also provided, which is configured to pair a payment instrument reading device with a payment initiating device.