PIC18F2550 RS-485 Adapter

Here is the first RS-485 monitor or adapter I built in small quanity.  I started with a RS-485 board from Modtronix, and used their prototype daughter board to add a USB connector (note: required two simple cuts to get USB to work).

My firmware for the PIC18F2550 adapts USB serial to RS-485 and vice versa (bidirectional).  It bridges the gap between the PC and 9-bit RS-485 protocols.

Also, here is a breadboarded version from scratch that uses identical firmware.  The RS-485 A/B wires are not show, would leave the LTC1487 chip at pins 6/7.  A USB B socket breakout board is used to help prototype the circuit.