Amendment 1 to Recommendation ITU-T G.8272/Y.1367 (2012) covers the case where the PRTC is integrated with a telecom grand master (T-GM) clock, therefore several clauses have been amended to reflect this.
ITU-T Y.1367 AMD 1-2013 history
2013ITU-T Y.1367 AMD 1-2013 Timing characteristics of primary reference time clocks Amendment 1 (Study Group 15)