UART TTL to WIFI Module Serial to wifi Support WPS Smart-LINK 802.11

1.1 Product Introduction

Realize TTL and WIFI Network Two-way Transmission

USR-WIFI232-T module is an integration of 802.11 b/g/n wi-fi module, which provides a wireless interface to any equipment with a serial interface for data transfer and has been widely applied in various fields.

It has the following functions:

  • Support IEEE802.11b/g/n Wireless Standards;
  • Support TCP/IP/UDP Network Protocols;
  • Support UART Data Interface;
  • Support Work As STA/AP/AP+STA Mode

Low Price, Small size, Smart Link Function, Support WPS Function

1.2 Product Features

Function Features

  • Support IEEE802.11b/g/n Wireless Standards
  • Support WIFI2.4 GHz, support WEP, WPA/WPA2 security mode.
  • Based on Self-developed High Performance MCU
  • Ultra-Low-Power for Battery Applications with Excellent Power Save Scheme
  • Support UART Data Communication Interface
  • Support Work As STA/AP/AP+STA Mode
  • Support SmartLink Function (APP program provide)
  • Support Wireless Upgrade Function
  • Support WPS Function
  • Support Multi-TCP Link (5 Channel) Apllication
  • Support External Antenna
  • Single +3.3V Power Supply
  • Smallest Size
  • FCC/CE Certificated

Product Parameters

Class Item Parameters
Wireless Parameters Certification FCC/CE
Wireless standard 802.11 b/g/n
Frequency range 2.412GHz-2.484GHz
Transmit Power 802.11b: +16 +/-2dBm (@11Mbps)
802.11g: +14 +/-2dBm (@54Mbps)
802.11n: +13 +/-2dBm (@HT20, MCS7)
Receiver Sensitivity 802.11b: -93 dBm (@11Mbps ,CCK)
802.11g: -85 dBm (@54Mbps, OFDM)
802.11n: -82 dBm (@HT20, MCS7)
Antenna External:I-PEX connector
Hardware Parameters Data Interface UART
Operating Voltage 3.0~3.6V
Operating Current Peak [Continuous TX]: ~200mA
Average. ~12mA, Peak: 200mA
Operating Temp. -40°C- 85°C
Storage Temp. -45°C- 125°C
Dimensions and Size 22mm x 13.5mm x 6mm
Software Parameters Footprint 1×10, 2mm connector
Network Type STA/AP/STA+AP
Security Mechanisms WEP/WPA-PSK/WPA2-PSK
Encryption WEP64/WEP128/TKIP/AES
Update Firmware Local Wireless
Customization Web Page Upgrade
Network Protocol IPv4, TCP/UDP/HTTP
User Configuration AT+command
Android/iOS APP
Smart Link APP tools

1.3 Application Structure

The module supports work as STA/AP/AP+STA Mode




1.4 Pin Definitions



The main pin function description


Module reset pin, input GPIO, low effective.

It needs to be pulled up when module works. A reset operation can be done by pulling this pin low for at least 10ms and then pull up.


Module recovery factory settings pin, input GPIO, low effective.

  • After module is powerd up, short press this button (Low < 3s) to make the module go into “Smart Link” configuration mode, waiting for APP to set password and other information.
  • After module is powerd up, long press this button (Low > 3s) to make the module recover to factory setting.


Wi-F link status indicator pin, output GPIO, low effective. This pin is strongly suggested to connect to an LED.

  • At “Smart Link” configuration mode, this LED used to indicate AP to finish setting.
  • At normal mode, it’s Wi-F link status indicator


Module start up success indicator pin, output GPIO, low effective. Can be connected out to led.


WPS function star pin, input GPIO, low effective. Can be connected to key.


UART pin


GPIO which can be controlled by network commands, n is control index number.


Module PWM signal output pin. Can also be configured as GPIO pin. Can switch

PWM_1 function to nLink, PWM_2 function to nReady, PWM_3 function to WPS keys, by AT command “AT + LPTIO = on”. AT + LPTIO = of” is the opposite.



[1] USR-WIFI232-T official website




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