Reference Clock Identifier : This is a 32-bit code identifying the particular reference clock. In the case of stratum 0 (unspecified) or stratum 1 (primary reference source), this is a four-octet, left-justified, zero-padded ASCII string. Stratum, Code, Meaning 0, DCN, DCN routing protocol 0, TSP, TSP time protocol 1, ATOM, Atomic clock (calibrated) 1, WWVB, WWVB LF (band 5) radio 1, GOES, GOES UHF (band 9) satellite 1, WWV, WWV HF (band 7) radio