JPS62120151A - Cordless optical telephone system - Google Patents

Abstract

PURPOSE:To attain the transmission/reception without limitation of a place in a room and a building over a wide range and without crosstalk and interception by applying transmission/reception between a master station and a telephone set through the utilization of optical space propagation. CONSTITUTION:A communication signal from a private branch of exchange 1 is sent to master stations 5-7 installed on a ceiling of each room through telephone lines 2-4. Then the signal is converted into an optical signal and irradiated toward portable optical telephone sets 8-13 via a space. The telephone sets 8-13 convert the received optical signal into a sound signal and outputted. Further, a voice from a talker is converted into an optical signal by the telephone sets 8-13 and irradiated toward the master stations 5-7. The master stations 5-7 convert the optical signal into an electric signal and outputs it to the private branch of exchange 1. Thus, the transmission/reception without crosstalk/interception is attained over a wide range in a room and in a building without limitation of the location of a telephone set.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a cordless optical telephone system that uses spatial propagation of light to transmit and receive calls.

``Prior Art'' Conventional cordless telephones have a configuration in which the cord is removed only between the telephone body and the handset, and, for example, the telephone body on a desk is still connected by a telephone line.

[Problems to be Solved by the Invention] Therefore, when changing the layout of the telephone installation location, the entire wiring must be changed, which is very troublesome.

Furthermore, when radio waves were used for communication in the cordless part, there were problems such as interference if the range was extended, and eavesdropping.

Means for Solving Problem E] The present invention eliminates the drawbacks of the prior art described above, and also enables transmission and reception over a wide range indoors and in buildings, and when the master station is located on the ceiling of the room. The purpose of this system is to provide a cordless optical telephone system that can make and receive calls without taking up space indoors, and includes a modulation circuit that receives and modulates electrical signals through a telephone line from a private branch exchange, etc., and the output of the modulation circuit. A light emitting unit converts the modulated signal into an optical signal and sends the light to the optical telephone, a light receiving unit receives the optical signal from the optical telephone and converts it into an electrical signal, and demodulates the electrical signal and outputs it to the telephone line. The cordless optical telephone system consists of a master station consisting of a demodulation circuit, and a telephone equipped with a light emitting and receiving section similar to the master station.

[Operation] The master station and the telephone perform optical communication through space using optical signals.

[Example] Hereinafter, an example according to the present invention will be described in detail according to the male drawings.

FIG. 1 is a diagram showing an embodiment of this example.

Call signals from the private branch exchange 1al are transmitted through telephone lines 2-4 to master stations 5-7 installed on the ceiling of each room. Here, the local stations 5-7 and the portable optical telephones 8-13 transmit and receive optical signals via space. A detailed block diagram of the structure of the master stations 5-7 is shown in FIG. The telephone line from the private branch exchange 1 is first input to the balance circuit 14, impedance matched, and taken into the master station. After being amplified by an amplifier 15 that amplifies the voice band, it is input to a modulation circuit 16, where it is converted into an optical signal, and then sent to a drive circuit 17, where it is converted into a corresponding optical signal by a light emitting element f18, and is used as a portable optical telephone. 8 to 13.

On the other hand, the optical signals from the mobile phones 8 to 13 are transmitted to the light receiving element 19.
The received signal is converted into an electrical signal and sent to a bandpass filter 20 that allows only predetermined carrier components to pass. Then, noise components other than the carrier component are removed, and only the predetermined carrier component is sent to the amplifier 21.
After being amplified to a predetermined level, the signal is demodulated by a demodulation circuit 22. The demodulated signal is then amplified by an amplifier 23 for amplifying the voice band, sent out to the telephone line through the balance circuit 14, and then output to the private branch exchange fit.

Next, the configuration of the portable optical telephones 818-13 in FIG. 1 will be explained with reference to FIGS. 3 and 4. Optical signals from the master stations 5 to 7 are received by the light receiving element 24, converted into electrical signals, and sent to a bandpass filter 25 that passes only the carrier component, where components other than the carrier component are removed. The output of the bandpass filter 25 is then amplified to a predetermined level by an amplifier 26 and demodulated by a demodulation circuit 27. The demodulated signal is then amplified by an amplifier 28 that amplifies the audio band, and then sent to a receiver 29, where it is converted into an audio signal and output.

Furthermore, the voice from the speaker is converted into an electrical signal by a transmitter 32, amplified by an amplifier 33 that amplifies the voice band, and sent to a modulation circuit 34. The signal is then modulated by a modulation circuit 34, passes through a light emitting element drive circuit 35, is converted into an optical signal by a light emitting element 36, and is emitted to the master stations 5-6.

FIG. 5 is an example of an external perspective view of the portable optical telephone of this embodiment. In the figure, 37 is a light transmitting/receiving section in which a light receiving element z4 and a light emitting element 36 are disposed, 38 is a receiving section in which a telephone receiver 19 is disposed, 39 is a transmitting section in which a transmitter 32 is disposed, and 40 is a transmitting and receiving section in which a light receiving element z4 and a light emitting element 36 are disposed. It's a button.

On the other hand, when making a call using a portable optical telephone, the telephone number of the called party is input using the pushbutton 40. The number information input from the button 40 is converted into an MF multiplied signal or dial signal by the encoder 31,
The signal is sent to the modulation circuit 34, modulated into a corresponding optical signal, and sent to the master station.

Another embodiment of the present invention As shown in Figure 6, the telephone line to each master station is not one line, but a total of three lines, 41 to 43, so that multiple lines can be used simultaneously anywhere in the building. You can now send and receive data.

An efficient and personal mobile phone can be realized.

Furthermore, it goes without saying that this embodiment can easily be adapted to the case where a digital electronic exchange is used as the private branch exchange with only a few changes.

As explained above, according to this embodiment, it is possible to completely eliminate telephone lines from the room, and there is no need for any special construction even if the telephone installation location is changed, and there are no restrictions on the installation location. It has the effect of not being affected.

Furthermore, since transmission is carried out using optical communication, there is no interference due to the allocation of emission wavelengths and modulation carrier frequencies, and the problem of external eavesdropping has been solved, making it possible to use it as a personal telephone.

``Effects of the Invention'' As described above, according to the present invention, there is no restriction on the location of the 'rrL phone, and there is an effect that interference with other devices and eavesdropping do not occur.

[Brief explanation of drawings]

FIG. 1 is an embodiment diagram of an example according to the present invention. Figure 2 is a block diagram of the configuration of the master station, Figure 3 is a block diagram of the light receiving section of the portable optical telephone, Figure 4 is a block diagram of the transmitting section of the portable optical telephone, and Figure 5 is the actual implementation. FIG. 6 is an external perspective view of a portable optical telephone according to an example. FIG. 6 is an embodiment diagram of another example according to the present invention. In the figure, l...Private electronic branch exchange, 5-7.44-46.
. . . Main station, 8-13. 47-52 . . . Portable optical telephone. Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) At least one master station that optically modulates the received signal from the telephone line and outputs the light, receives and demodulates the optically modulated optical signal, and transmits it to the telephone line, and optical modulation from the master station 1. A cordless optical telephone system comprising at least one telephone set that demodulates a signal and outputs audio from a receiver, optically modulates a signal from a transmitter, and emits light to the base station. (2) A patent characterized in that a master station is installed on the ceiling of each room or a building having a predetermined spatial area, and calls can be made between each telephone device via the master station. A cordless optical telephone system according to claim 1.