The present invention may be deployed in an interface between a security module (CH) housed on a chip card (CC) and a host device (HST) comprising a chip card reader (RDR). In the case where the security module (CH) operates at frequencies which are high enough to generate unwanted electromagnetic interference, the invention allows for a substantial reduction in such interference by providing a converter module (CVT) which allows the host device to operate at lower frequencies while a limited number of short, shielded connections are used to interface with the security module (CH).