A memory address generator for a multiport data communication system storing received data packets in a memory having a plurality of storage areas. The first coupling member is optionally a tubular component and the second coupling member or coupler is optionally a belled component. The width of the cradle is greater than the diameter of the saw blade. In accordance with the present invention, the insertion instrument can be separated from the prosthetic implant by rotation of only one time after the prosthetic implanted is completely inserted, so that the operation process of implanting the prosthetic implant is easy and safe. In addition, a transmission device in the host device may be activated to transmit detectable signals to help recover the host device.