Please be advised that this radio configuration (RC3) is not adapted for United States.
WF923 module is an Uplink only module which enables SIGFOX communication in Japan, to enjoy longer battery thanks to low energy consumption solution. Either external or inaternal antenna is available for your choice. Interface is UART, I2C, Digital I/O, and AD input. The Japan regional(ARIB) already certified with RC-3c, evolution to 192kHz.
End Product Certificate M_0031_CC23_01
Dimensions (in mm): 35 x 20 x 2
Max Tx Radiated Power: +13 dBm
Power Supply: From 2.2V to 3.8V
Tx: 32 mA
Idle: 1 μA
A connector for an external antenna is available