The following table summarizes the reference clocks that a clock master can drive:
Clock |
Details |
---|---|
A_CLOCK |
The set of primary bit clocks (CT8A) and framing signals (CTFrameA). The CT8A signal is an 8 MHz clocking reference for transferring data over the CT bus. The CTFrameA provides a low going pulse signal every 1024 (8 MHz) clock cycles. |
B_CLOCK |
The set of secondary bit clocks (CT8B) and framing signals (CTFrameB). The CT8B signal is an 8 MHz clocking reference for transferring data over the CT bus. The CTFrameB provides a low going pulse signal every 1024 (8 MHz) clock cycles. |
The following table summarizes the timing references that a clock master can use:
Timing reference |
Details |
---|---|
NETWORK |
The timing signal from a digital trunk attached to the clock master board. Within the digital trunk interface, an 8 kHz reference is derived from the frequency of the incoming signal. The clock master is frequency-locked to this 8 kHz reference so that the long-term timing of the system matches that of the public telephone network. Note: No timing signal is available from an analog trunk. |
NETREF / NETREF1 |
The CTNETREF_1 signal. Can be 8 kHz, 1.544 MHz, or 8 MHz. NMS recommends using only 8 kHz signals for most boards. |
NETREF2 |
(H.110 only) The CTNETREF_2 signal. Can be 8 kHz, 1.544 MHz, or 8 MHz. NMS recommends using only 8 kHz signals for most boards. |
OSC |
Clock signal derived from an oscillator on the clock master board. Note: Use this timing reference source only if no network timing references are available. |
Note: Not all boards support all signals. For more information about board models, refer to the board documentation.