When using MicroScanner Pro connected to hub sometimes the unit shows 10/100 to hub signal and other times it shows 10/100 to PC signal
This is caused by "dueling auto-sense" circuits.
Whether the link partner is determined to be MDI (a PC, or "normal" connection), or an MDI-X (a hub/switch, or "uplink" connection) is traditionally determined by whether the TX signal is sensed on pair 1,2 or pair 3,6.
Many modern hubs and switches are capable of auto-sensing the attached link partner's signal, and will accommodate either by internally switching which pair is used by the hub/switch. The sensing is usually accomplished by the simple expedient of alternately offering the TX signal on each of the two pair choices.
Whether the link partner is determined to be MDI (a PC, or "normal" connection), or an MDI-X (a hub/switch, or "uplink" connection) is traditionally determined by whether the TX signal is sensed on pair 1,2 or pair 3,6.
Many modern hubs and switches are capable of auto-sensing the attached link partner's signal, and will accommodate either by internally switching which pair is used by the hub/switch. The sensing is usually accomplished by the simple expedient of alternately offering the TX signal on each of the two pair choices.
