To provide a central terminal which can regulate the upward transmission power of a subscriber side apparatus to the optimal level automatically, and to provide a communications system and a method of communication.
A line length measuring sensor 45 TDR measures the line lengths L11-L13 of the telephone lines of subscriber side apparatuses 11-13, immediately after the power of the central terminal 1 is turned on, and applies the power to a memory circuit 46. A control circuit 43 sets the PBO reference length LR1 of the central terminal 1 based on the line lengths L11-L13 stored in the memory circuit 46, and performs an upward transmission power control. Therefore, the line length of each telephone line is measured, irrespective of the connection state of the subscriber side apparatus or ON/OFF state of the power supply, and the reference length of the optimal PBO is automatically determined from its line length information to each service area. Consequently, the upward transmission power of the subscriber side apparatus is automatically regulated to the optimal level.
| JP2013034243 | FAULT ANALYSIS SYSTEM AND FAULT ANALYSIS METHOD |
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| JP2916231 | [Title of Invention] Telephone system |
UEDA MASAMI
Toshio Morita
Yoshihei Nakamura
Yutaka Horii
Hisato Noda
Masayuki Sakai