The module features two distinct sides: the (for your microcontroller) and the RS232 side (for the external serial device). 1. TTL Side (Microcontroller Connection)
The HW-044 datasheet highlights its ability to bridge the gap between high-voltage RS232 signals (up to ±25V) and low-voltage TTL signals (0-5V). Specification MAX3232 (Texas Instruments or similar) Operating Voltage 3.0V – 5.5V DC Baud Rate Support Up to 120 kbps (standard) or 250 kbps TTL Connector 4-pin header (VCC, GND, TX, RX) RS232 Connector Female DB9 (Standard Serial Port) Operating Temp -40°C to +85°C Dimensions ~31mm x 32mm HW-044 Pinout and Interface hw-044 datasheet