A data communication apparatus is provided, which is capable of properly transmitting and receiving data of low speed specifications such as MIDI data even via a transmission line of high speed specifications such as an IEEE 1394 serial bus, and hence capable of properly processing the data. Some of the compounds of the present invention and some of their methods of preparation are also novel an nonobvious. The apparatus is preferably located as early as possible in the production chain in order to obtain results as close as possible to the cows. A new quantization matrix Q1 is selected from the local minimizers bounded by a target quantization matrix Qbound. The window regulator may include a powered lead screw regulator, a rack and pinion regulator or a cable and drum regulator. Methods of measuring internal structural characteristics and methods of correlating fatigue damage to results from excitation tests are also taught.