A TTL to RS485 converter module is a device that is used to convert a TTL (Transistor-Transistor Logic) signal to an RS485 (Recommended Standard 485) signal, or vice versa. The module typically consists of a driver and receiver circuit that are used to transmit and receive data over long distances using the RS485 protocol. The module can be used with an Arduino or other microcontroller to allow it to communicate with devices that use the RS485 protocol. The RS485 protocol is commonly used in industrial and commercial environments because it allows for the transmission of data over long distances (up to 1200 meters) and can support multiple devices on a single communication line.

 x 4 Header (Data side)

• RO  =  Receiver Output.  Connects to a serial RX pin on the microcontroller
• RE  =  Receiver Enable.  Active LOW.  Connects to a digital output pin on a microcontroller. Drive LOW to enable receiver, HIGH to enable Driver
• DE  =   Driver Enable.  Active  HIGH.  Typically jumpered to RE Pin.
• DI  =   Driver Input.  Connects to serial TX pin on the microcontroller

1 x 4 Header (Output side)

• VCC =  5V
• B      =  Data ‘B’ Inverted Line. Common with the B
• A      =  Data ‘A’ Non-Inverted Line.  Connects to A on far end module
• GND =  Ground

1 x 2 Screw Terminal Block (Output side)

• B      = Data ‘B’ Inverted Line. Connects to B on far end module
• A      = Data ‘A’ Non-Inverted Line.  Connects to A on far end module

With an on-board MAX485 chip , this is a tool for RS-485 communications at low-power. Also known as a Slew-Rate Transceiver