A bio-signal measurement system, characterized in that the bio-signal measurement system comprises a bio-signal measurement apparatus, which comprises tool-less connectors (100A, 100B, 100C), 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 (100A, 1003, 100C), 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 (100A, 100B, 100C) are electrically coupled with the controllable coupling selection arrangement, which is configured to electrically couple all the tool-less connectors (100A, 100B, 100C) 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 (100A, 100B, 100C) 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 (100A, 100B, 100C) 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 (100A, 100B, 100C), 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 (100A, 1003, 100C), 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 (100A, 100B, 100C) are electrically coupled with the controllable coupling selection arrangement, which is configured to electrically couple all the tool-less connectors (100A, 100B, 100C) 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 (100A, 100B, 100C) 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 (100A, 100B, 100C) 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.