A biosignal measurement system comprises an adapter for a biosignal measurement device, and an external support structure separate from the adapter. The adapter comprises tool-less connectors, which are repeatedly connectable to and disconnectable from their counter connectors of the external support structure, and a device connector, which has an electrical connection with the tool-less connectors and which has a connection with the biosignal measurement device that the adapter carries. The external support structure comprises an electrode support structure with electrodes and tool-less counter connectors, the electrodes and the tool-less counter connectors having an electrical connection therebetween. The electrodes form an electrical contact with skin for receiving the biosignal. The counter connectors are in electrical contact with the connectors of the adapter for transferring the biosignal to the biosignal measurement device through the adapter.