Dynamic decoding of communication between card reader and portable device

Abstract

The proposed technology generally relates the field of data transmission, in particular it relates to decoding an encoded data signal received at an audio interface of a portable electronic device, wherein the encoded data signal is encoded with an encoding scheme having an adjustable encoder clock frequency. The proposed method comprises pre-processing the received encoded data signal; scanning the received encoded data signal for a known start sequence and when a known start sequence is successfully detected then calculating an actual frequency based on the detected start sequence; interpreting, a data block succeeding the start sequence using the assessed actual frequency; and assessing whether to request adjustment of the adjustable encoder clock frequency based on the scanning and/or the interpretation. The proposed technology relates to a method performed in a portable communications device well as a corresponding device and computer program.