Description: Secondary reference for the clock source. Each of these codes are to be interpreted as follows: liu-rclk0: Recovered clock from physical line 0 liu-rclk1: Recovered clock from physical line 1 liu-rclk2: Recovered clock from physical line 2 liu-rclk3: Recovered clock from physical line 3 liu-rclk4: Recovered clock from physical line 4 liu-rclk5: Recovered clock from physical line 5 liu-rclk6: Recovered clock from physical line 6 liu-rclk7: Recovered clock from physical line 7 dsx3: Recovered clock from the T3/E3 line bp8clk: Back-plane 8 KHz clock none : No secondary clock is configured