The converter enables communication between computers and serial devices that support the RS-485 serial interface standard. The adapter converts RS-232 signals to the RS-485 standard, allowing for an extension from 5 meters (RS-232 side) to up to 1,200 meters (RS-485 side). The converter does not require an external power supply. By using a patented RS-232 chipset, the initialization of the RS-232 interface is eliminated. The integrated transceiver allows for delay-free operation and automatic detection of the data transfer direction from the I/O ports. The detection does not require handshake signals and ensures full compatibility for RS-232 half-duplex applications without any changes to the software. Therefore, no modifications to software or hardware are necessary before using the device. The converter supports a serial transmission rate of 300 to 115200 bps. Its applications range from industrial systems to card reading systems, access systems, digital payment systems, and machine engineering applications.