COMMUNICATION APPARATUS, METHOD OF SPECIFYING ASSOCIATED APPARATUS, AND NETWORK SYSTEM

PROBLEM TO BE SOLVED: To solve a problem wherein an initial setting is conventionally forced on a user in order to recognize an apparatus present in the same room. SOLUTION: A fixed apparatus 200 includes: a light reception element 201 for receiving light; a light reception-side communication part 207 for multicasting a first light reception message showing that the light reception element 201 has received light to a communication network when the light reception element 201 has received light, and receiving a second light reception message showing that another apparatus has received light via the communication network; and a light reception-side determination part 204 determining that the own apparatus and the other apparatus exist in a reaching zone of light received by the light reception element 201 when the difference between the time at which the light reception element 201 has received the light and the time at which the light reception-side communication part 207 has received the second light reception message is in an assumed communication delay period. COPYRIGHT: (C)2010,JPO&INPIT