Dual mode radio communication apparatus having function of selectively designating analog or digital mode

A dual mode cellular radio telephone apparatus used in a cellular radio system wherein speech signals are selectively communicated with a base station in either one of an analog transmission mode or a digital transmission mode over one or more radio channels and the speech signals are selectively subject to a digital signal processing for a secret communication, comprising:

• establishing means for establishing a speech communication with the base station over a radio link on the basis of a transmission mode designated by the base station;
• first user-actuatable switch means for selectively requesting the analog transmission mode and the digital transmission mode;
• first transmitting means for transmitting a mode designation signal for requesting the analog transmission mode when the analog transmission mode is requested by said first user-actuatable switch means and for transmitting a mode designation signal requesting the digital transmission mode when the digital transmission mode is requested by said first user-actuatable switch means;
• second user-actuatable switch means for requesting the secret communication;
• second transmitting means responsive to an actuation of the second user-actuatable switch means for transmitting the mode designation signal requesting the digital transmission mode over the radio link;
• determining means for determining whether the radio link is established between said dual mode cellular radio telephone apparatus and said base station in the digital transmission mode after the mode designation signal requesting the digital transmission mode is transmitted by said second transmitting means;
• and
• informing means for informing a speaker of capability of the secret communication when said determining means determines that the radio link is established in the digital transmission mode, and for informing the speaker of incapability of the secret communication when said determining means determines that the radio link is not established in the digital transmission mode.

A radio communication apparatus used in a dual mode cellular radio system for selectively transmitting a communication signal in an analog or digital mode through a radio link established between a base station and said radio communication apparatus, comprising:

• a mode designation input apparatus for selectively designating and inputting a desired mode from the analog mode and the digital mode;
• a mode comparison circuit for comparing the desired mode with the mode currently used in transmission of the communication signal when said mode designation input apparatus designates and inputs the desired mode during the transmission of the communication signal;
• and
• a change control circuit for transmitting to said base station a mode change request signal for changing the mode currently used in the transmission of the communication signal into the desired mode when said mode comparison circuit detects that the mode currently used in the transmission of the communication signal does not coincide with the desired mode, and for inhibiting the mode change request signal from being transmitted to said base station when said mode comparison circuit detects that the mode currently used in the transmission of the communication signal coincides with the desired mode.

A dual mode cellular radio telephone apparatus used in a cellular radio system wherein speech signals are selectively communicated with a base station in either one of an analog transmission mode or a digital transmission mode over one or more radio channels and the speech signals are selectively subject to a digital signal processing for a secret communication, comprising:

• communication circuitry for establishing a speech communication with said base station over a radio link on the basis of a transmission mode designated by said base station;
• a first user-actuatable switch for selectively requesting the analog transmission mode and the digital transmission mode;
• a first transmitter for transmitting a mode designation signal for requesting the analog transmission mode when the analog transmission mode is requested by said first user-actuatable switch and for transmitting a mode designation signal requesting the digital transmission mode when the digital transmission mode is requested by said first user-actuatable switch;
• a second user-actuatable switch for requesting the secret communication;
• a second transmitter responsive to an actuation of the second user-actuatable switch for transmitting the mode designation signal requesting the digital transmission mode over the radio link;
• a controller for controlling said communication circuitry and for determining whether the radio link is established between said dual mode cellular radio telephone apparatus and said base station in the digital transmission mode after the mode designation signal requesting the digital transmission mode is transmitted by said second transmitter;
• and
• a display for informing a speaker that the secret communication is enabled when said controller determines that the radio link is established in the digital transmission mode, and for informing the speaker that the secret communication is not enabled when said controller determines that the radio link is not established in the digital transmission mode.