Telefast Interfaces with Relay Inputs for SSR and/or EM Relays Schneider Electric Telefast 2 Pre-Wired System The Telefast 2 system of pre-cabling is composed of modules connected to the PLC by means of a multicore cable equipped with HE 10 connectors . The Telefast 2 interfaces make it possible to simplify the operation of wiring and thus limiting errors.