2-Wire Digital Communication (DCF active)

Since DCF77 was originally defined as a radio broadcast signal, specific signal levels for DCF77 are not defined in any standard. The most common techniques for transmission of DCF77 (DCLS) is its multi-point distribution as a 24V signal over shielded twisted-pair cable. This signal is wired to a general-purpose or dedicated digital input, configured to decode the DCF77 signal.