To provide a communication system, a communication terminal and computer software wherein a hearer can instruct a control means to increase/decrease a signal level while making a speech, the control means of an opposite terminal adjusting the signal level of a microphone so as to allow the hearer to easily hear a received voice without the need for making a request under a communication environment wherein transmission/reception of data other than voice is available while making a voice speech like the Internet.

In the communication system comprising a plurality of communication terminals each provided with: an analog/digital converter 5 for converting a voice signal picked up by a microphone 3 into digital data; an encoder 7; a transmission means 9 for transmitting the signal to an opposite communication terminal 32 via a communication path 100; a reception means 9; a decoder 12; and a digital/analog converter 14 for converting the digital data into the original voice signal, and each outputting the voice signal to a speaker 16 or an earphone and attaining a speech between the communication terminals, each communication terminal includes: a function 21 of remotely controlling the sensitivity of the microphone of the opposed communication terminal; and a function 5 receiving remote control over the sensitivity of the microphone of its own terminal from the opposed communication terminal.