I have some assumptions I would like validated/invalidated about near- end vs. far-end timing in T1/E1-based systems. Please let me know if any of my statements are incorrect:
- In either near-end or far-end system, data is essentially received by recovering a clock from the incoming data stream, and using that to receive the data.
- In a near-end system (if we provide timing), we can use our internal clock source to generate the transmit timing to the far-end. Ideally, the far-end should recover the timing that they receive (that we transmit), and use that to transmit data back to us (to the near-end); therefore, the near-end timing should be identical to the far-end timing (in frequency).
- In a far-end system, the far-end provides timing on the data they transmit to the near-end; so we should use that (instead of our internal clock source) to generate timing on the transmit side.
- A problem can occur if we are in a far-end timing setup, but we are still using internal timing for data we transmit. In this case, the far-ends frequency CAN be slightly different than our internal clocks, which would cause data to be out of sync.
Do I understand this mess?
J