A bio-signal measurement system, characterized in that the bio-signal measurement system comprises a bio-signal measurement apparatus , which comprises tool-less connectors , the number of which is three, for an electric contact with a separate docking apparatus or an electrode arrangement , coupling targets , which include a battery and a data communication unit that is configured to record a bio-signal received from the electrode arrangement when they are connected with each other through the tool-less connectors , and perform electrically a plug-and-play data transfer with the separate docking apparatus , a controllable coupling selection arrangement , and a control arrangement comprising a logic circuit or a computer program; and the tool-less connectors are electrically coupled with the controllable coupling selection arrangement , which is configured to electrically couple all the tool-less connectors with only one of the coupling targets at a time in response to control from the control arrangement ; and the battery is configured to receive electricity from the tool-less connectors for charging the battery through the electric coupling caused by the coupling selection arrangement under control of the control arrangement during a first time window when the bio-signal measurement apparatus is connected with the docking apparatus , and the data communication unit is configured to send and/or receive data through the tool-less connectors using the plug-and-play data transfer based on the electric coupling caused by the coupling selection arrangement under control of the control arrangement during a second time window when the bio-signal measurement apparatus is connected with the docking apparatus . tool-less connectors , the number of which is three, for an electric contact with a separate docking apparatus or an electrode arrangement , coupling targets , which include a battery and a data communication unit that is configured to record a bio-signal received from the electrode arrangement when they are connected with each other through the tool-less connectors , and perform electrically a plug-and-play data transfer with the separate docking apparatus , a controllable coupling selection arrangement , and a control arrangement comprising a logic circuit or a computer program; and the tool-less connectors are electrically coupled with the controllable coupling selection arrangement , which is configured to electrically couple all the tool-less connectors with only one of the coupling targets at a time in response to control from the control arrangement ; and the battery is configured to receive electricity from the tool-less connectors for charging the battery through the electric coupling caused by the coupling selection arrangement under control of the control arrangement during a first time window when the bio-signal measurement apparatus is connected with the docking apparatus , and the data communication unit is configured to send and/or receive data through the tool-less connectors using the plug-and-play data transfer based on the electric coupling caused by the coupling selection arrangement under control of the control arrangement during a second time window when the bio-signal measurement apparatus is connected with the docking apparatus . <EOS>