Communication apparatus utilizing digital optical signals

Communication apparatus utilizing digital optical signals, said apparatus comprising:

• first input analog circuit means at a first location for receiving an input analog electrical signal;
• first digital circuit means coupled to said input circuit means for converting said analog electrical signal to a digital electrical signal;
• first optical transmission circuit means coupled to said first digital circuit means for generating and transmitting a first baseband digitally formatted optical signal;
• enabling circuit means coupled to said first optical transmission circuit means for enabling said first optical transmission circuit means to transmit a connection command signal;
• first optical receiving circuit means located remotely from and in line-of-sight alignment with said first optical transmission circuit means for sensing and receiving said baseband digitally formatted optical signal and for converting said baseband digital formatted optical signal to a digital electrical signal, and
• second digital circuit means coupled to said first optical receiving circuit means for converting said digital electrical signal to an output analog electrical signal, said output analog electrical signal replicating said input analog electrical signal;
• said first digital circuit means further comprising a pulse-width-modulation modulator and said second digital circuit means further comprising a pulse-width-modulation demodulator.

Communication apparatus utilizing digital optical signals, said apparatus comprising:

• first input circuit means for receiving an input analog electrical signal;
• first digital circuit means coupled to said input circuit means for converting said analog electrical signal to a digital electrical signal;
• first optical transmission circuit means coupled to said first digital circuit means for generating and transmitting a first baseband digitally formatted optical signal;
• first optical receiving circuit means located remotely from and in line-of-sight alignment with said first optical transmission circuit means for sensing and receiving said baseband digitally formatted optical signal and for converting said baseband digital formatted optical signal to a digital electrical signal,
• second digital circuit means coupled to said first optical receiving circuit means for converting said digital electrical signal to an output analog electrical signal, said output analog electrical signal replicating said input analog electrical signal;
• enabling circuit means coupled to said first optical transmission circuit means for enabling said first optical transmission circuit means to transmit a connection command signal;
• microprocessor circuit means coupled to said first optical receiving circuit means for sensing and responding to said connection command signal to generate an enable command signal;
• second optical transmission circuit means coupled to said microprocessor circuit means for receiving said enable command signal in response to said microprocessor sensing said connection command signal to enable said second optical transmission circuit means to transmit a digitally formatted optical signal acknowledging said connection command signal, and
• second optical receiving circuit means located in the vicinity of said first optical transmission circuit means and remotely from and in line-of-sight alignment with said second optical transmission circuit for receiving said digitally formatted optical signal carrying said acknowledgement response signal to said connection command signal whereby a two-way optical communication link between said first optical transmission circuit means and said first optical receiving circuit means and between said second optical transmission circuit means and said second optical receiving circuit means is established.

Communication apparatus utilizing infrared digital optical signals for establishing a bidirectional optical communication path between a first and second location remote from one another, said apparatus comprising:

• a terminal unit at the first location, said terminal unit including:
• means for receiving a first analog electrical signal;
• means coupled to said first analog receiving means for converting said first analog electrical signal to a first baseband digitally formatted optical signal;
• first means for transmitting said first baseband digitally formatted optical signal;
• first means for enabling said first transmitting means to transmit a first connection command signal;
• a station unit at the second location, said station unit including:
• means for receiving said first baseband digitally formatted optical signal;
• means coupled to said first optical receiving means for converting said received first baseband digitally formatted optical signal into a second analog electrical signal, said second analog electrical signal replicating said first analog electrical signal;
• means for receiving a third analog electrical signal;
• means coupled to said third analog receiving means for converting said third analog electrical signal to a second baseband digitally formatted optical signal;
• second means for transmitting said second baseband digitally formatted optical signal;
• second means for enabling said second transmitting means to transmit a second connection command signal;
• said terminal unit further including:
• means for receiving said second baseband digitally formatted optical signal;
• means coupled to said second optical receiving means for converting said received second baseband digitally formatted optical signal into a fourth analog electrical signal, said fourth analog electrical signal replicating said third analog electrical signal to establish a two-way communication connection between the first and second locations via the bi-directional optical communication path.

In combination with a telephone instrument of the general type arranged to accept coin, credit card and the like for accessing connection to the public telephone switching network, apparatus for establishing a bi-directional optical communication path between a user and the telephone switching network, said apparatus comprising:

• a station unit;
• a terminal unit located remotely from said station unit;
• said station unit having circuit means for electrically interfacing a telephone line associated with the public telephone switching network and the telephone instrument to electrically and physically couple the telephone line to the telephone instrument, said station unit having first and second operative states, said first state corresponding to the telephone line being electrically connected to the telephone instrument in the normal manner and said second state corresponding to the telephone line being electrically connected said station unit circuit means;
• said terminal unit having means for optically coupling said terminal unit to said station unit, said terminal unit further comprising:
• microphone means for sensing audio frequency signals and for converting said audio signals to baseband frequency electrical signals, said microphone means having an output;
• receiver earpiece means for sensing baseband frequency electrical signals carrying information in the audio frequency spectrum to convert said sensed electrical signals to sound for hearing by a user;
• a key pad having circuit means for generating dual tone multi-frequency (DTMF) signals at an output to dial a telephone number;
• supervisory circuit means for generating a baseband frequency supervisory signal representative of an "off-hook" condition for initiating a call connection with said station unit, said supervisory signal being used for sustaining said optical coupling between said station unit and said terminal unit;
• digital modulation circuit means for converting said baseband frequency supervisory signals and said baseband frequency audio signals to digitally modulated electrical signals;
• optical circuit means coupled to said digital modulation circuit means for converting said digitally modulated electrical signals into digitally modulated optical signals for transmission to said station unit;
• optical receiving means for sensing optical signals and for converting said sensed optical signals into digitally modulated electrical signals representative of supervisory and audio frequency signals originating at said station unit;
• first digital demodulation circuit means for converting said digitally modulated electrical signals into supervisory and audio baseband frequency signals;
• said station unit means including:
• optical detecting means for receiving a digitally modulated optical signal from said terminal unit to transform said optical signal to a corresponding digitally modulated electrical signal;
• second digital demodulation circuit means for converting said digitally modulated electrical signal into supervisory and audio baseband frequency signals;
• circuit means response to an "off-hook" supervisory signal for causing said station unit to operate to its second operative state and for coupling baseband frequency electrical signals appearing on the telephone line to said second digital modulation circuit means for converting said baseband frequency signals to digitally modulated electrical signals;
• optical transmission circuit means for converting said digitally modulated electrical signals to digitally modulated optical signals for transmission to said terminal unit, whereby audio frequency signals appearing on said telephone line are received at the earpiece of said terminal unit and audio frequency signals at the microphone of said terminal unit are received at said telephone line.

Communication apparatus utilizing digital optical signals, said apparatus comprising:

• first input circuit means for receiving an input analog electrical signal;
• first digital circuit means coupled to said input circuit means for converting said analog electrical signal to a digital electrical signal;
• first optical transmission circuit means coupled to said first digital circuit means for generating and transmitting a first baseband digitally formatted optical signal;
• enabling circuit means coupled to said first optical transmission circuit means for enabling said first optical transmission circuit means to transmit a connection command signal;
• first optical receiving circuit means located remotely from and in line-of-sight alignment with said first optical transmission circuit means for sensing and receiving said baseband digitally formatted optical signal and for converting said baseband digital formatted optical signal to a digital electrical signal, and
• second digital circuit means coupled to said first optical receiving circuit means for converting said digital electrical signal to an output analog electrical signal, said output analog electrical signal replicating said input analog electrical signal.

A communication method utilizing digital optical signals, said method comprising the steps of:

• receiving a first analog electrical signal at a first location;
• converting said first analog electrical signal to a first baseband digitally formatted optical signal;
• transmitting said first baseband digitally formatted optical signal;
• receiving said first baseband digitally formatted optical signal at a second location remote from said first location,
• converting said received first baseband digitally formatted optical signal into a second analog electrical signal, said second analog electrical signal replicating said first analog electrical signal;
• the step of converting said first analog electrical signal further including processing said first analog electrical signal utilizing a continuously variable slope delta (CVSD) modulation encoder and digitally encoding said first analog electrical signal at a predetermined frequency, and
• the step of receiving said first baseband digitally formatted optical signal including sensing said transmitted first baseband digitally formatted signal at said predetermined frequency thereby establishing an optical communication link between the first and second location when said digitally formatted signal is sensed at said predetermined frequency at the second location and dropping said optical communication link when said digitally formatted signal is not sensed at said predetermined frequency at the second location.

A communication method utilizing digital optical signals, said method comprising the steps of:

• receiving a first analog electrical signal at a first location;
• converting said first analog electrical signal to a first baseband digitally formatted optical signal;
• transmitting said first baseband digitally formatted optical signal;
• receiving said first baseband digitally formatted optical signal at a second location remote from said first location, and
• converting said received first baseband digitally formatted optical signal into a second analog electrical signal, said second analog electrical signal replicating said first analog electrical signal;
• the step of converting said first analog electrical signal further including processing said first analog electrical signal utilizing a pulse-width-modulation (PWM) encoder and digitally encoding said first analog electrical signal at a predetermined frequency, and
• the step of receiving said first baseband digitally formatted optical signal including sensing said transmitted first baseband digitally formatted signal at said predetermined frequency thereby establishing an optical communication link between the first and second location when said digitally formatted signal is sensed at said predetermined frequency at the second location and dropping said optical communication link when said digitally formatted signal is not sensed at said predetermined frequency at the second location.