Communication system, speech input device, communication terminal, and program

A communication system, comprising:

• a communication terminal capable of communicating with an Internet Protocol, IP, transceiver;
• and
• a voice input device for inputting a voice into the communication terminal,
• the communication terminal and the voice input device being connected to each other via a phone connector, the IP transceiver being configured to carry out communication over a mobile phone network,
• the voice input device including:
• a microphone element configured to convert the voice into an electric signal;
• a transmission switch configured to switch between transmitting or not transmitting the electric signal from the voice input device to the communication terminal;
• and
• a connection state maintenance circuit for causing the communication terminal to recognize, regardless of a state of the transmission switch, that a connection between the voice input device and the communication terminal is maintained,
• the communication terminal including:
• a connection detection section configured to detect a state in which the voice input device and the communication terminal are connected to each other;
• a level determination section configured to determine a level of the electric signal in a state in which the voice input device is connected to the communication terminal;
• and
• a transmission control section configured to control, in accordance with a result of determination by the level determination section, transmission of the electric signal to the IP transceiver.