Radio Telephone Set for Digital Communication Which Alerts the User of Incoming Digital Data Signals

The invention relates to a radio telephone set, and more particularly to a radio telephone set indicating digital communication to be presently carried out in non-talking mode.

In a conventional radio telephone set, a received digital signal is converted to an analog signal in a codec included therein, when the talking mode is designated by an operator, and the analog signal is supplied to a telephone set circuit which is connected to an external terminal thereof, so that a talking between a caller and a callee is carried out.

On the other hand, when the digital communication mode is designated by the operator, a received digital signal is directly supplied to a personal computer or a facsimile apparatus which is connected to the external terminal without passing through the codec, so that the digital signal is processed in the personal computer or the facsimile apparatus.

In the conventional radio telephone set, however, there is a disadvantage in that a state in case where a digital signal is presently received in the non-talking mode is not externally indicated, for instance, in accordance with audio representation or visual display. Consequently, an operator who wants to make a telephone call can not know the mode state before his call is denied connection to the telephone line.

Accordingly, it is an object of the invention to provide a radio telephone set for digital communication in which digital data receiving state is externally indicated using an audio representation or a visual display.

It is a further object of the invention to provide a radio telephone set for digital communication in which an operator can know the digital data receiving state before actually trying to make a telephone call.

According to the invention, a radio telephone set for digital communication comprises:

means for providing a demodulated digital signal by receiving a transmitted digital signal,

means for generating an analog signal in accordance with the demodulated digital signal, when the demodulated digital signal is for telephone information;

means for generating an indication signal in accordance with the demodulated digital signal, when the demodulated digital signal is for digital data;

means for indicating a state in which the demodulated digital signal for the digital data is received by receiving the indication signal;

a telephone set for carrying out telephone communication by receiving the analog signal; and

an external machine for processing the demodulated digital signal for digital data.

The invention will be explained in more detailed in conjunction with appended drawing, wherein:

FIG. 1 is a block diagram showing a radio telephone set for digital communication in a preferred embodiment according to the invention.

FIG. 1 shows a radio telephone set for digital communication in a preferred embodiment according to the invention which comprises a demodulation circuit 1 for demodulating a digital signal received by an antenna 10, a digital signal processor 2 including a tone signal generator 2A for converting a demodulated digital voice signal into an analog voice signal and for generating a tone signal in the tone signal generator 2A in case where the demodulated digital signal is not for the talking voice, a switch 3 for selecting one of the demodulated digital non-voice signal and the analog voice signal an external terminal 4 to which an external machine such as a telephone set, a personal computer, a facsimile apparatus, etc. is connected, an amplification circuit 5 for amplifying a signal supplied from a switch 8 for selecting one of the tone signal and the analog signal from the digital signal processor 2, a speaker 6 for generating voice or sound in accordance with the signal amplified in the amplification circuit 5, and a central processing unit (CPU) 7 for controlling the digital signal processor 2, the switches 3 and 8, etc. by receiving a mode designating signal supplied from a mode switch 9.

In operation, a digital signal received by the antenna 10 is demodulated in the demodulation circuit 1. When the demodulated digital signal is for voice, the demodulated digital signal is converted to an analog signal in the digital signal processor 2. The analog signal is supplied via the switch 3 to the external terminal 4 and via the switch 8 to the amplification circuit 5 and then to the speaker 6. Thus, an operator can receive voice information by using a telephone set 11 connected to the external terminal 4, while voice or sound is made in accordance with the analog signal amplified in the amplification circuit 5 by the speaker 6.

On the other hand, when the demodulated digital signal is not for voice, the digital signal is supplied via the switch 3 to the external terminal 4, while a tone signal is generated in the tone signal generator 2A of the digital signal processor 2 to be supplied via the switch 8 and the amplification circuit 5 to the speaker. Thus, the digital signal is processed in a personal computer 12 or a facsimile apparatus 13 connected to the external terminal 4, while tone sound is made by the speaker 6. Consequently, the operator can know the digital data receiving state, so that an operator does not attempt to place a telephone call during this state.

In place of or together with the speaker 6, a visual display may be provided to visually indicate the digital data receiving state. In non-digital data receiving state or non-talking state, the operator can select one of digital data transmission mode and telephone mode by using the mode switch 9.

Although the invention has been described with respect to specific embodiment for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modification and alternative constructions that may be occur to one skilled in the art which fairly fall within the basic teaching here is set forth.