How to Use:
ESP8266's GND, RX, TX, and 5V are respectively connected to the GND, TX, RX, and 5V of the external TTL serial port module. IO0 must be connected to GND when downloading. After the download is complete, disconnect the connection between IO0 and GND.
Relay Output:
NC: Normally closed end. The relay is short‑connected with COM before the pull‑in, and then suspended after pull‑in
COM: Public
NO: Normally open end, the relay is suspended before being closed, and shorted to COM after being closed

Specification:
Item Type: Relay Module
Material: PCB
Working Voltage: DC 7-28V / 5V
Purpose: Suitable For The Secondary Development Of ESP8266
Suitable Scenario: Smart Home Wireless Control

Package List:
1 x Relay Module
1 x Pin
6 x Socket