"Two working mode : Mode 1:cellphone carry on wifi module directly Mode 2: cellphone and wifi module carry on router together Additional function :work as USB module when remove ESP-01 module" "Transmission distance: (1) the open environment, when the mobile phone carrying on the WIFI module ,maximum transmission distance is 100 m; (2), when the WiFI module and cell phone carrying on the router at the same time, the signal transmission distance depends on router signal" Use the Smartconfig technology to complete the configuration of the account and password of the esp-01 WIFI module on the mobile APP. The configured account and password will be memorized after power off The board contains 12V,10A/250V AC 10A/30V DC relay, which can continuously absorb 100,000 times, with the protection of diode current and short response time. With mode option and working statue LED indicator.With 4 isolator and strong anti interference ability.Reserved UART debug interface and MCU download port for program, Manufacturer: DollaTek