Wireless terminal device

A wireless terminal device comprising:

• an input portion configured to receive an input from a sensor;
• an output portion configured to convert a signal inputted to the input portion from the sensor, to a radio signal, and output the radio signal;
• a circuit board module electrically connected to the input portion and the output portion;
• an external power supply module detachably connected to the circuit board module, and including an input terminal for receiving an input from an external power supply, the external power supply module being configured to convert an input voltage inputted to the input terminal and output an output voltage;
• and
• a case in which a storage space for storing the external power supply module is formed, the case being configured to store the input portion, the output portion, the circuit board module, and the external power supply module, wherein
• the storage space allows a battery to be stored therein when the external power supply module is detached from the circuit board module, and
• the circuit board module includes a connector connection portion that allows one of a connector of the external power supply module and a connector of the battery to be selectively connected thereto, the connector connection portion being provided at a position spatially connected to the storage space.