Alphanumeric audio response terminal unit

Claim 2

In an audio terminal unit for entering information into a data transmission network through the handset of a telephone operatively coupled to a central processor and including: a keyboard having a plurality of alphanumeric keys and control keys thereon, encoding means responsive to the actuation of any one of said keys on said keyboard for generating a plurality of frequency control signals in response to said actuated key, a tone generator response to each of said frequency control signals for generating a multiple frequency signal representing said actuated key, and an acoustic transducer responsive to said tone generator for coupling the frequency signals therefrom to the handset, said encoding means comprising: a first encoder responsive to the activation of any one of said keys on said keyboard for generating a first frequency control signal, a delay means responsive to said first frequency control signal for generating a delay signal for a predetermined time interval, a second encoder responsive both to the continued activation of said one key and the initiation of said delay signal for generating a second frequency control signal, and a third encoder responsive both to the continued activation of said one key and the termination of said delay signal for simultaneously terminating the generation of said second frequency control signal and for generating a third frequency control signal, the generation of said first and third frequency control signals by said first and third encoders continuing until the deactivation of said one key, whereby said tone generator emits one tone constantly, and sequentially emits two other tones during each depression of a key.

Claim 3

In an audio terminal unit for enteriNg information into a data transmission network: a plurality of control switches, a tone generator for generating a multiple frequency signal individually representative of each switch in said plurality of switches, encoding means responsive to the actuation of a selected one of said control switches for generating a set of at least three frequency control signals individually representative of the actuated switch and utilizing such set of frequency control signals for causing the tone generator to produce the multiple frequency signal representative of such actuated switch, said encoding means comprising: a first encoder responsive to the actuation of the selected control switch for generating the first frequency control signal of said set of frequency control signals which is representative of the actuated switch, circuit delay means operable for a predetermined time period and starting its operation in response to the initiation of said first frequency control signal, a second encoder responsive to both the continued actuation of the selected switch and the start of the operation of said circuit delay means for generating the second frequency control signal of the set of frequency control signals which is representative of the actuated switch, a third encoder for generating the third frequency control signal of the set of frequency control signals which is representative of the actuated switch, and circuit means responsive to both the continued actuation of the selected switch and the expiration of said time delay period for simultaneously terminating the generation of said second frequency control signal by said second encoder and for initiating the generation of said third frequency control signal by said third encoder, the generation of said first and third frequency control signals by said first and third encoders continuing until the deactivation of said selected switch, whereby said tone generator emits one tone constantly and sequentially emits two other tones during the actuation of each said switch.

Claim 4

In an audio terminal unit for enteriNg information into a data transmission network: a plurality of control switches, a tone generator for generating a multiple frequency signal individually representative of each switch in said plurality of switches, encoding means responsive to the actuation of a selected one of said control switches for generating a set of at least three frequency control signals individually representative of the actuated switch and utilizing such set of frequency control signals for causing the tone generator to produce the multiple frequency signal representative of such actuated switch, said encoding means comprising: a first encoder responsive to the actuation of the selected control switch for generating the first frequency control signal of said set of frequency control signals which is representative of the actuated switch, circuit delay means operable for a predetermined time period and starting its operation in response to the initiation of said first frequency control signal, a second encoder responsive to both the continued actuation of the selected switch and the start of the operation of said circuit delay means for generating the second frequency control signal of the set of frequency control signals which is representative of the actuated switch, a third encoder for generating the third frequency control signal of the set of frequency control signals which is representative of the actuated switch, and circuit means responsive to both the continued actuation of the selected switch and the expiration of said time delay period for simultaneously terminating the generation of said second frequency control signal by said second encoder and for initiating the generation of said third frequency control signal by said third encoder, the generation of said first and third frequency control signals by said first and third encoders continuing until the deactivation of said selected switch, whereby said tone generator emits one tone constantly and sequentially emits two other tones during the actuation of each said switch.