A force sensing system comprising a force sensor cell with the necessary electronics to acquire and process various signals. The method includes cutting the assembly along first and second indicia disposed at the ends of a pipe section and removing a center segment of the pipe section, leaving first and second end fittings with a gap therebetween. The resonators are arranged in a planar array having spaced apart side edges and spaced apart top and bottom edges. The OLT includes a unit for measuring and accumulating the reception light amplitude and data on the inter-frame gap of an appropriate length decided in advance according to the characteristic of the light reception device and generates a grant value for assuring an inter-frame gap of an appropriate length by using the both information.