The advanced use of the NSG 4070 may require the operation with two power ampli.. ers. The SW 4070 allows to switch the signal paths for having a remote controlled system and is fully powered and controlled by the NSG 4070. Interlock connections provide to switch off the ampli.. er gain. Additionally the SW 4070 is supplied with a second user port socket for connecting e.g. the MD 4070 or using the EUT monitoring functions of the NSG 4070os user port.