The present invention is a cross-connect protection method that protects a cross-connect in a system where a plurality of network management terminals monitor a plurality of network elements constituting a network and the cross-connect at each of the network elements is controlled. In this context, an intake-manifold pressure and an ambient pressure are modeled. A cover lip is formed on one end of the handle and a cable loop is formed on the other end thereof. The first attenuator is disposed between the first amplifier and the filter for reducing return loss of the microwave signal processor. Therefore, a carry signal having a reduced ripple component is supplied to the next stage, so that a transient current is intercepted at a transistor receiving the carry signal, which is arranged in the next stage, thus ensuring reliability of the shift register. An annular ring member has a relatively lower gas permeability than that of the O-ring and is provided in the inner bore of the rotary slide ring so as to adjoin the O-ring at an atmosphere side of the sealing device, wherein the following expression D1<D2<D3 is satisfied.