A MIMO communication system having deterministic channels the orthogonality of which can be ensured even if a reflected wave other than the direct wave is present during line-of-sight communication is provided. In order to judge the normalcy of the radio characteristic of the radio access point, a test is performed through the calling connection between a testing access terminal in the radio access point and a predetermined device. The optical viewing instrument may have an observation tube and an ocular attached thereto. The word lines are arranged in rows in the array. The priority encoder provides an indication of the received interrupt with the highest priority to a vector generator.