US 5,331,672 A · Automatic detector and selector of RS-232 or V.35 interface

Abstract

An automatic detection and selection circuit resident in a DCE is provided. The circuit is coupled to the DCE interface connector and detects receipt by the DCE of V.35 and RS-232 transmit data signals, distinguishes between those signals, and selects circuitry for passing the data therethrough. The circuit comprises a switch coupled to a first TX data terminal (pin 2 or P) of the DCE interface connector, first and second line receiving circuits, a microprocessor, and a relay. The first line receiving circuit is coupled to a first pole of the switch and to the second TX data terminal (pin S) of the DCE interface connector and provides indications as to whether or not an input signal is present at at least one of pins P and S. The second line receiving circuit is coupled to the second pole of the switch and provides indications as to whether or not a valid RS-232 transmit data signal is detected. The microprocessor is coupled to the outputs of the line receiving circuits, and based on the indications output thereby, appropriately controls the relay, and hence the switch. The microprocessor first checks in a V.35 mode as to whether a data signal is being received. It then checks in a RS-232 mode as to whether the data signal is a valid RS-232 signal. If not, it switches the circuit back to the V.35 mode.

Claims20

Dependent claims

An automatic detection circuit resident in a DCE and coupled to an interface connector of the CE for detecting receipt by the DCE of V.35 and RS-232 transmit data signals, and distinguished between those signals, the automatic detection circuit comprising:

a) switch means coupled to a first TX data terminal of said DCE interface connector, said switch means having at least a first pole and a second pole;
b) a first line receiving circuit means coupled to said first pole of said switch means and to a second TX data terminal of said DCE interface connector, wherein said first line receiving circuit means provides a first signal indicating that no. V.35 or RS232 transmit data signal is being received when neither said first and second TX data terminals receives an input signal, and provides a second signal indicating that a transmit data signal is being receives when an input signal is present at at least one of said first and second TX data terminals;
and
c) a second line receiving circuit means coupled to said second pole of said switch means for providing a third signal indicating that said transmit data signal is a RS-232 signal when a valid RS-232 transmit data signal is detected, and a fourth signal when a valid RS-232 transmit data signal is not detected, wherein the presence of said second signal followed by said fourth signal indicates that said data transmit signal is a V.35 signal.

1 more element

An automatic detection and selection circuit resident in a DCE and coupled to an interface connector of the DCE for detecting receipt by the DCE of V.35 and RS-232 transmit data signals and distinguishing between those signals, and for selecting circuitry for passing the data therethrough, the automatic detection and selection circuit comprising:

a) switch means coupled to a first TX data terminal of said DCE interface connector, said switch means having at least a first pole and a second pole;
b) a first line receiving circuit means coupled to said first pole of said switch means and to a second TX data terminal of said DCE interface connector, wherein said first line receiving circuit means provides at an output a first signal indicating that no V.35 or RS-232 transmit data signal is being received when neither said first and second TX data terminals receives an input signal, and provides a second signal indicating that a transmit data signal is being receives when an input signal is present at at least one of said first and second TX data terminals;
and
c) a second line receiving circuit means coupled to said second pole of said switch means for providing a third signal indicating that said transmit data signal is a RS-232 signal when a valid RS-232 transmit data signal is detected, and a fourth signal when a valid RS-232 transmit data signal is not detected;
and
d) logic control means for switching said switch from contacting said first pole to contacting said second pole when said second signal is provided by said first line receiving circuit means, and for switching said switch means from contacting said second pole to contacting said first pole when, after said second signal is provided by said first line receiving circuit means, said second line receiving circuit means provides said fourth signal, wherein the presence of said second signal followed by said fourth signal indicates that said data transmit signal is a V.35 signal.

3 more elements

a) switch means coupled to a first Tx data terminal of said DCE interface connector, said switch means having at least a first pole and a second pole;
b) a first line receiving circuit means coupled to said first pole of said switch means and to a second TX data terminal of said DCE interface connector, wherein said first line receiving circuit means provides at an output a first signal indicating that no V.35 or RS-232 transmit data signal is being received when neither said first and second TX data terminals receives an input signal, and provides a second signal indicating that a transmit data signal is being receives when an input signal is present at at least one of said first and second TX data terminals;
and
c) a second line receiving circuit means coupled to said second pole of said switch means for providing at an output a third signal indicating that said transmit data signal is a RS-232 signal when a valid RS-232 transmit data signal is detected, and a fourth signal when a valid RS-232 transmit data signal is not detected wherein the presence of said second signal followed by said fourth signal indicates that said data transmit signal is a V.35 signal;
d) microprocessor means coupled to said output of said first line receiving circuit means, for receiving said first signal and said second signal of said first line receiving circuit means and determining therefrom whether a data signal is being received by said automatic detection and selection circuit, and for generating a control signal in response thereto;
and
e) relay means coupled to said microprocessor means and controlling said switch means, for causing said switch means to switch data flow from said first pole to said second pole when said microprocessor mans generates a control signal requiring the same.

4 more elements

Dependencies are inferred from the claim text.

Automatic detector and selector of RS-232 or V.35 interface

Life of this patent

Automatic detector and selector of RS-232 or V.35 interface

Life of this patent

Abstract

Claims20