A connector is for connection to a plate-like connection object. A quick-acting valve releases the pneumatic medium, which is under working pressure, into the pressure channel, wherein a control circuit controls the duration of opening of the valve as a function of at least one or a combination of the following parameters: working pressure, impact frequency or pressure in the back-pressure chamber. The second device receives a first type or second type of credit depletion notification from the first device indicating that the first device needs additional credits to transmit further frames to the second device.