Patent attributes
A system includes a plurality of line cards and a timing card. A clock generation circuit on the timing card generates a clock signal which is pulse width modulated according to information to be transmitted. A clock line supplies the pulse width modulated clock signal to the line cards. The timing card sends a first control word to the plurality of line cards over the clock line after sending a beacon. The first control word includes a size field specifying a first length of first data following the first control word. The timing card sends time of day information over the clock line to the line cards following the first control word. The time of day information may be encrypted. A second control word follows the time of day information. One or more additional control words can follow the second control word before the next beacon.
