These works are part of a PhD thesis performed at the INERIS, under the scientific supervision of the UTT, and about the reliability of digital-based transmitters. These systems are commonly described as “intelligent” since they are able to perform innovative functionalities such as self-diagnoses, error measurement corrections, self-adjustments, and on-line reconfigurations. Moreover, they may take advantage of a bidirectional digital communication to perform “cooperating” operations. First, an “intelligent transmitter” modelling has been developed, which includes material and functional interactions, and reliability analyses have been proposed based on this model, dealing with uncertainties linked to system behaviours under faulty conditions. Then, “intelligent transmitters” taking part of control systems have been considered, taking the system elements interactions into account, as well as the process influences, using a dynamic reliability framework.