Non-contact sensing and reading of signals transmitted by a cable

A method for sensing modulated signals in a process facility. The method includes providing a monitoring device that includes a non-contact electromagnetic sensor (EM sensor) configured to sense a modulated signal transmitted on a cable including a conductor coupled to a sensing device or apparatus in the process facility. The monitoring device further includes a non-transitory machine readable storage device and a processor. The non-transitory machine readable storage device stores a data decoding program including protocol information for identifying different communication protocols. The monitoring device is positioned in proximity to the cable for the EM sensor to detect the modulated signal. The data decoding program is implemented by the processor causing the processor to detect the modulated signal and condition the modulated signal to provide a conditioned modulated signal. The conditioned modulated signal is decoded to generate decoded signal data, and the decoded signal data is displayed.