A tubular component of a drill stem comprises a first end including a first threading, a second end including a second threading, and a substantially tubular central zone, the component further comprising a device for electrical connection with another component, mounted on at least one of the ends, and a cable for the transmission of signals between the first end and the second end, connected to the connecting device, the connecting device including at least one conductor provided with an electrically insulated link portion and an electrical contact portion; a dielectric to isolate the insulated link portion; and an annular sealing surface defining a protected zone, said electrical contact portion being disposed in the protected zone, the annular sealing surface being disposed at the surface of the insulated link portion.