Russell,

You are misinformed. RS-422 CAN have multiple devices connected, since it is a four wire differential serial link. The drawings you show from B&B Electronics with the caption "4-wire RS-485" are in my opinion misleading, they should stick to the standard, they are RS-422 period. Any other labelling is misleading and causes confusion. That's why the standards were created and agreed upon in the first place to create commonality.

Jacob