Hw-044 Datasheet -

Flashing routers, set-top boxes, and satellite receivers.

: Flashing firmware on set-top boxes, routers, and hard drives via their internal serial headers.

To summarize:

The HW-044 module typically has four pin headers on one side for TTL connection and a DB9 female connector on the other. TTL Side (Header Pins) 3.3V - 5.5V Power Supply. GND: Ground. TXD: TTL Transmission Pin (Connect to Microcontroller RX). RXD: TTL Receiving Pin (Connect to Microcontroller TX). RS232 Side (DB9 Female)