Claims
- 1. A communications system for automotive vehicles, which comprises:
- (a) a fixed communications unit which transmits an area signal at all times and an information signal if requested; and
- (b) a mobile communications unit which transmits a request signal when the area signal is received within a communications area, and receives the information signal from said fixed unit in accordance with the request signal, the electric field strength transmitted from said fixed communications unit being predetermined higher than that transmitted from said mobile communications unit in the case where the threshold level determined in said fixed communications unit for receiving signals transmitted from said mobile communications unit is equal to the threshold level determined in said mobile communications unit for receiving signals transmitted from said fixed communications unit.
- 2. A communications system for automotive vehicles as defined in claim 1, wherein:
- (a) said fixed communications unit includes a first ultra-high frequency transmit/receive means for transmitting the area signal to said mobile unit, receiving the request signal from said mobile unit, and transmitting the information signal to said mobile unit, and
- (b) said mobile communications unit includes a second ultra-high frequency transmit/receive means for receiving the area signal from said fixed unit, transmitting the request signal to said fixed unit, and receiving the information signal from said fixed unit.
Priority Claims (1)
Number |
Date |
Country |
Kind |
54-35387 |
Mar 1979 |
JPX |
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Parent Case Info
This is a division of application Ser. No. 133,259 filed Mar. 24, 1980 now U.S. Pat No. 4,359,712.
US Referenced Citations (3)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2614918 |
Oct 1977 |
DEX |
Divisions (1)
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Number |
Date |
Country |
Parent |
133259 |
Mar 1980 |
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