Electroacoustic converter

Claim 2

An electroacoustic converter for the transmitting of digital data over a standard telephone line to a central data processing system comprising means for converting a sequence of bilevel electrical signals to a first and a second audible signal, said converting means including a modulator means having a voltage controlled multivibrator with a means for maintaining said multivibrator in a first audible frequency output condition for a predetermined period of time, said converting means further including a pulse standardizing means for providing a pulse output signal in response to a fixed level input signal and a first flip-flop circuit, having a set and a reset input connected thereto with the output of said pulse standardizing means connected to the set input of said first flip-flop circuit and the output of said first flip-flop circuit connected to said modulator maintaining means for holding said voltage controlled multivibrator in said first output condition for said predetermined period of time.

Claim 3

The electroacoustic converter as set forth in claim 1 including still further a one shot multivibrator circuit and a second flip-flop circuit having a set and a reset input connected thereto with the output of said one shot multivibrator circuit connected to the set input of said second flip-flop, said one shot multivibrator circuit also connected to the reset input of said first flip-flop wherein the activation of said one shot multivibrator causes said first flip-flop circuit to be placed in a reset condition while simultaneously placing said second flip-flop circuit in a set condition.

Claim 4

An electroacoustic converter for the transmitting of digital data over a standard telephone, via a telephone exchange to a central data processing system comprising a modulator means capable of providing a first audible output frequency called a MARK and a second audible output frequency called a SPACE in response to a bilevel input signal to said modulator, a MARK HOLDING means included with said modulator for maintaining said modulator output frequency in a MARK condition for a predetermined period of time a first flip-flop having a set and a reset input and an output means, the output of a first flip-flop circuit connected to said MARK HOLDING means to activate the same, a pulse standardizing means connected to the set input of said first flip-flop to cause said first flip-flop to be placed in a set condition, a two input AND gate connected to the input of said pulse standardizing means to activate said pulse standardizing means upon simultaneous receipt of a voltage level and a data terminal ready signal applied at the input of said AND gate, a one shot multivibrator with its input also connected to the output of said AND gate and its output connected to the reset input of said first flip-flop wherein the simultaneous activation of saiD pulse standardizer and said one shot multivibrator causes said first flip-flop to be set by said pulse standardizer and subsequently reset by said one shot multivibrator at a fixed predetermined period.

Claim 5

An electroacoustic converter for the transmitting of digital data over a standard telephone, via a telephone exchange to a central data processing system comprising a modulator means capable of providing a first audible output frequency called a MARK and a second audible output frequency called a SPACE in response to a bilevel input signal to said modulator, a MARK HOLDING means included with said modulator for maintaining said modulator output frequency in a MARK condition for a predetermined period of time a first flip-flop having a set and a reset input and an output means, the output of a first flip-flop circuit connected to said MARK HOLDING means to activate the same, a pulse standardizing means connected to the set input of said first flip-flop to cause said first flip-flop to be placed in a set condition, a two input AND gate connected to the input of said pulse standardizing means to activate said pulse standardizing means upon simultaneous receipt of a voltage level and a data terminal ready signal applied at the input of said AND gate, a one shot multivibrator with its input also connected to the output of said AND gate and its output connected to the reset input of said first flip-flop wherein the simultaneous activation of saiD pulse standardizer and said one shot multivibrator causes said first flip-flop to be set by said pulse standardizer and subsequently reset by said one shot multivibrator at a fixed predetermined period.

Claim 6

The electroacoustic converter as set forth in claim 3 wherein a second flip-flop, having a reset and a set input means, is connected to said one shot multivibrator with the output of said one shot multivibrator commonly connected to the reset input of said first and set input of said second flip-flops causing said second flip-flop to be set by the same signal that resets said first flip-flop to thereby provide from said second flip-flop a CLEAR TO SEND signal to said central data processing system.

Claim 7

The electroacoustic converter as set forth in claim 4 wherein an error indication means is included therein.

Claim 8

The electroacoustic converter as set forth in claim 5 wherein said error indication means includes a band-pass filter, an amplifier connected thereto, a flip-flop circuit connected with its set input to be set upon the receipt of a signal from said amplifier, a lamp driver means with an error indicating lamp connected to the output of said flip-flop to be illuminated by the activation of said lamp driving means upon the setting of said flip-flop circuit.

Claim 9

The electroacoustic converter as set forth in claim 6 wherein said error indicating means further includes a manual resetting means to reset said flip-flop circuit.