| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional communication method for portable telephone terminals that public telephone lines are not effectively used and radio channels of a portable telephone system are deficient, especially, in the city area where there are many subscribers of terminals to make it difficult to connect to an opposite side. SOLUTION: An access point which uses infrared rays, etc., is installed in a public telephone booth and a terminal carried in the booth receives the control signal from the access point and switches its system from a communication system using a radio wave to a communication system using the infrared rays, etc., automatically, and the public telephone line is connected to the access point side and used effectively and a radio channel deficiency of the portable telephone system in a city area is reduced. |
