Phase 3: Monitor check

The MAU's relais is opened by a phantom voltage; the adapter now receives (and repeats) all frames passing the ring. The adapter waits for at least 18 seconds for one of the following MAC frames:

- Active Monitor Present (AMP)

- Standby Monitor Present (SMP)

- Ring Purge

If one of these MAC frames is received, the new adapter knows that an active monitor is present. If none of these are received, the new station will initiate monitor contention.

Monitor Contention Process: Claim Token