The HESC-T-002 is a serial converter designed to interface RS-232C (TXD/RXD) signals with 3.3V TTL/CMOS compatible levels. Operating without an external power supply, the converter delivers a precision 0–3.3V TTL output. The device utilizes a proprietary RS-232 charge pump driver, eliminating the need to initialize the serial port for power.

Featuring internal zero-delay automatic transceiver switching, the converter's unique I/O circuitry automatically manages data flow direction without the need for hardware handshaking (such as RTS or DTR). This ensures that full-duplex RS-232 software can run in 3.3V TTL mode without modification, maintaining total compatibility with existing operating software and hardware interfaces. This series supports baud rates ranging from 300 bps to 115,200 bps.