This low power transceiver module is based on the Maxim MAX485 IC to allow serial communication over very long cable runs (up 4000 feet / 1200 meters). Serial data can be transmitted in both directions (half duplex) at a data rate up to 2.5Mbps. The modules operate from a standard 5V power supply and use 5V logic levels allowing them to be interfaced to the hardware serial ports of microcontrollers such as Arduino/PIC etc. Direction of communication can be controlled with just one digital pin (see diagram). It is also possible to connect multiple modules together for communication between 2 or more devices. For even greater distances two modules can be configured as a repeater.
Each module contains one driver and one receiver. Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit.
Data connections to the modules are provided by a standard 0.1″ pitch header pins which can also be soldered into standard prototyping PCB and breadboards. Screw terminals provide convention connection to the actual data cable.
A…………Non-inverting Receiver Input and No-ninverting Driver Output.
B…………Inverting Receiver Input and Inverting Driver Output
R0……….Receiver Output (to Rx pin of microcontroller)
RE……….Receiver Output Enable (Low to enable)
DE……….Driver Output Enable (high to enable)
DI………..Driver Input (to Tx pin of microcontroller)