Full duplex vs. half duplex — which ordering code fits your bus
Full duplex (ADM4857ARZ-REEL7) uses separate pairs for transmit and receive, allowing simultaneous bidirectional data flow. The half-duplex sibling ADM4853ARZ-REEL7 shares a single pair and requires direction control via the driver enable pin. If your application uses a four-wire RS-422 topology or a full-duplex RS-485 master-slave arrangement, this is the correct ordering code. For two-wire multi-drop RS-485 networks, the half-duplex variant saves one twisted pair.
The part is ROHS3 compliant.