INTERFACE FOR CONDUCTING SERIAL DIGITAL DATA COMMUNICATIONS THROUGH AUDIO JACK

Abstract: A digital/audio signal interface for craftperson's butt-in test set is configured to allow either audio signals or serial digital communication signals, such as those associated with the downloading of software for reconfiguring or upgrading the functionality of the test set, to be ported through a standard audio jack. The interface includes a controlled connectivity digital signal transport path coupled between the audio jack and digital processor circuitry of the butt set. During a selected communication mode (audio or digital), the interface is operative to decouple the audio jack from test set circuitry associated with the other signal type (digital/audio).

Description: INTERFACE FOR CONDUCTING SERIAL DIGITAL DATA COMMUNICATIONS THROUGH AUDIO JACK The present invention relates to telecommunication systems and support equipment therefor, and is directed to a digital/ audio signal interface, that may be incorporated into a communication device, such as a craftperson's butt-in test set, and is configured to allow either audio signals or serial digital corrununication signals, such as those associated with the downloading of software for reconfiguring or upgrading the functionality of the test set, to be ported through a standard analog audio jack. During a selected communication mode (audio or digital), the interface is operative to decouple the audio jack from test set circuitry associated with the other signal type (digital/ udio). Accompanying the continuing and rapid-paced advance of the telecommunications technology is the ongoing need to upgrade or reconfigure equipment and system components. To accommodate this requirement, while avoiding a wholesale replacement of its internal electronics, a device implementation will customarily include one or more non- volatile memory modules that store a control program employed by an associated micro-controller, which serves as the principal functionality determining component of the device. For upgrading the device firmware, it has been traditional practice to physically remove and reprogram or replace one or memory modules. Recent improvements in 'flash' memory technology, however, have now made it possible to externally re-program system components, as by way of a host computer, using a serial digital communication interface. As a non-limiting example, Figure 1 diagrammatically illustrates a programmable butt-in telephone test set (or butt set) 10, having of a user interface 11 (including a keypad, associated display and audio transceiver components), through which a telephone craf tperson may test a variety of telephone circuits, including those associated with both analog (plain old telephone service) or POTS and digitally formatted communication services. As further shown in the reduced complexity functional system diagram of Figure 2, in addition to the customary wireline coupling port 12 through which a telco circuit 13 of the butt set may be connected to (e.g., bridged onto tip and ring leads of) a wireline pair 14 under test, and a standard three-conductor audio jack 15 through which the user may interface audio signals (for example, with an audio headset 16) with an audio circuit 19, it has been customary practice to provide an additional auxiliary digital port 17 (such as an RS-232 port), through which serial digital communication access via digital interface circuitry 18 to internal memory and control processor circuitry 20 is afforded. Associated with the ability to externally reprogram the functionality of the device are packaging issues of product miniaturization and environmental sealing, which make minimizing the aggregate footprint of external connectors increasingly important. The present invention relates to a method of interfacing digital communication signals with digital circuitry associated with control of a utility device, said utility device preferably constituted by a telephone butt set having a multiport audio jack through which analog audio signals are ported over an audio signal transport path with audio circuitry of said utility device, said method characterized by the steps of: (a) providing a controlled connectivity digital signal transport path between said audio jack and said digital circuitry of said utility device; and (b) in association with the application to said audio jack of digital communication signals to be coupled to said digital circuitry of said utility device, enabling transport connectivity therefor over said digital signal transport path between said audio jack and said digital circuitry of said utility device, while effectively inhibiting the transport of analog signals over said audio signal transport path with said audio circuitry of said utility device. The invention also includes a signal interface for interfacing digital communication signals with digital circuitry associated with operation of a utility device, said utility device having a multiport audio jack through which analog audio signals are ported over an audio signal transport path with audio circuitry of said utility device, characterized by a controlled connectivity digital signal transport path coupled between said audio jack and said digital circuitry of said utility device, and a control circuit, coupled to each of said audio and digital signal transport paths and being operative, in association with the application to said audio jack of digital communication signals, to enable transport connectivity therefor over said digital signal transport path between said audio jack and said digital circuitry of said utility device, while effectively inhibiting transport of analog signals over said audio signal transport path with said audio circuitry of said utility device. Conveniently, as improved digital/ audio signal interface, is configured to selectively couple either audio signals or serial digital communication signals, such as those associated with the downloading of software for reconfiguring or upgrading the functionality of a test set, through a standard three terminal analog audio jack that has been customarily used only for porting audio signals. The default mode of the interface may be configured for analog signaling; however, when it is desired to conduct a digital data communication session with an external device, such as a host computer upgrade of the test set's control software, the interface is operative to decouple the audio jack from the test set's internal audio circuitry and, instead, provide a digital communication path between the audio jack and the internal digital components of the test set. Pursuant to a first embodiment, the interface of the invention is configured to controllably interface signaling ports of a standard three-port audio jack through controllably switched full duplex signal paths for respective audio and digital transceiver circuits. For this purpose, the audio jack has a first port coupled through an input audio path of a controlled switching device to an input audio buffer amplifier, and a second port coupled through an output audio path of the controlled switching device from an output audio buffer amplifier. In order to provide controllable auxiliary signalling connectivity to internal digital circuitry of the test set, the input and output signal paths of the two audio ports of the audio jack are further coupled through input and output digital switch paths of the switch to a pair of digital signal buffer amplifiers, respectively associated with digital signal receive and transmit circuits of the test set. In addition, the signal ports of the audio jack are further coupled to a data communication detector, for the purpose of providing automatic control of the paths through the switch. For automatic switch path control, the data communication detector is operative to monitor the audio jack's signaling ports for the presence of prescribed characteristics of digital data communication signals, such as those associated with a data transmission session with a host computer. In response to detecting these signalling parameters, the detector informs the control processor, which establishes the states of the paths through the switch that interrupt audio path connectivity and instead couple the input and output ports of the audio jack to the receive and transmit paths through the digital circuitry. In accordance with a second embodiment, rather than control switch path connectivity of a switching circuit installed between the audio jack's signaling ports and the internal analog and digital circuitry of the device, the operation of the buffer amplifiers is directly controlled. For this purpose, a controlled switch may be coupled between a power terminal for the input and output audio buffer amplifiers, while the input and output digital buffer amplifiers are controllably enabled by the processor. A third embodiment of the invention is configured for half-duplex mode operation, where only one of the audio jack's signal ports, such as the microphone port, is available. As in the second embodiment, the analog buffer amplifiers are selectively controlled by a controlled switch coupled in circuit with their power leads. In addition, the single audio jack port is coupled to each of the selectively enabled digital input buffer amplifier and through a transistor to the transmission path of the digital output circuitry of the device. The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 diagrammatically illustrates a programmable butt-in telephone test set; Figure 2 is a reduced complexity functional diagram of the internal circuitry architecture of the butt set of Figure 1; Figure 3 diagrammatically illustrates a first, full duplex embodiment of the digital/ audio interface of the present invention; Figure 4 diagrammatically illustrates a second, full duplex embodiment of the digital/ audio interface of the present invention; and Figure 5 diagrammatically illustrates a third, half-duplex embodiment of the digital/ audio interface of the present invention. Before describing in detail the new and improved digital/ audio signal interface of the present invention, it should be observed that the inventive interface resides primarily in a modular arrangement of conventional communication circuits and components. In terms of a practical implementation that f acilitates its manufacture as a printed circuit-based package that may be readily incorporated into a communication device, such as, but not limited to a craftperson's butt set, this modular arrangement may be readily implemented as field programmable gate array (FPGA) and application specific integrated circuit (ASIC) chip set. Figure 3 diagrammatically illustrates a first, non-lirniting embodiment of the digital/ audio interface of the present invention, which is configured to controllably interface signaling ports of a standard three-conductor audio jack 30 with both audio and digital circuitry of a communication device (such as a craftperson's butt set). As shown therein, the audio jack has a first port 31 adapted to be coupled over an audio receiver (e.g., microphone) audio signal path 41 to an input audio buffer amplifier 51 of an audio/ digital communication device (such as a craftperson's butt set). The audio jack further includes a second port 32, that is adapted to be coupled over an audio transmitter (e.g., speaker) signal path 42 from the output of an output audio buffer amplifier 52, and a third port 33 adapted to be coupled to a voltage reference terminal 43, such as ground, as shown. In order to provide controllable signalling connectivity to internal digital circuitry of the test set, the respective input and output signal paths 41 and 42 for the audio jack 30 are coupled to the audio buffer amplifiers 51 and 52 through respective paths 61 and 62 of a controllable switch 60, shown as comprising a set of four ganged switches 61 - 64, as a reduced complexity example. The operation of the switch 60 is controlled by an input select signal supplied by way of a control link 65 from an associated processor-controlled driver. Signal paths 41 and 42 are further coupled through respective paths 63 and 64 of the switch 60 to a pair of digital signal buffer amplifiers 53 and 54, that are respectively associated with digital signal receive and transmit circuits of the test set. As shown, the switch path pair 63/64 is controlled so as to be closed when switch path pair 61/62 is open, and vice versa. The signal paths 41 and 42 are further coupled to a data communication detector 70, that may be employed to control the automatic control of the paths through the switch 60. Data communication detector 70 is operative to monitor leads 41 and 42 for the presence of prescribed characteristics of digital data communication signals, such as those associated with a data transmission session with a host computer. In response to detecting these signalling parameters, detector 70 changes the logic state of its output 73 to inform the control processor of a digital communication download session. The processor then establishes the state of the switch control line 65 to open switch paths 61 and 62 and thereby decouple paths 41 and 42 from the respective audio buffer amplifiers 51 and 52, and close switch paths 63 and 64 and thereby couple paths 41 and 42 to the digital signal buffer amplifiers 53 and 54. Once the data session has been terminated, the state of leads 41 and 42 will so indicate, and detector 70 will change the logic state of its output 73 to inform the control processor of the termination of the digital communication session, and cause the states of the paths through the switch 60 to return to the default analog state. Figure 4 diagrammatically illustrates a second embodiment of the digital/ audio interface of the present invention. As shown therein, rather than control switch path connectivity of a switching circuit installed between the paths 41 and 42 and the internal analog and digital circuitry, the operation of the buffer amplifiers 51-54 themselves is controllably enabled. For this purpose, a controlled switch 80 may be coupled between a power terminal 81 for the input and output audio buffer amplifiers 51 and 52, while the input and output digital buffer amplifiers 53 and 54 are controllably enabled by a transceiver enable lead 83 from the processor. Figure 5 diagrammatically illustrates a third, half-duplex mode embodiment of the digital/ audio interface of the present invention, for the case that only one of the pair of signal conductors 41 and 42 associated with respective ports 31 and 32 of the audio jack is available, such as but not limited to the microphone line 41 shown in the example of Figure 5. Similar to the embodiment of Figure 4, the operation of the analog buffer amplifiers 51 and 52 is selectively controlled by a controlled switch 80 installed between the power terminal 81 and the input and output audio buffer amplifiers. In addition, the input lead to the digital input buffer amplifier 53, which is coupled in circuit with the input (microphone) signal path 41, is coupled to VCC through a pull-up resistor 85. The input signal path 41 is further coupled through a transistor 90 to the transmission path of the digital output circuitry of the device. Since the same signal path 41 is employed for host-to-device digital communications (e. g., software downloads) to the selectively enabled digital buffer amplifier 53, and also device-to-host transmissions through transistor 90, digital communications through the interface are conducted in half-duplex mode over the shared signal path 41 associated with terminal 31 of the audio jack. By providing digital communication connectivity through a standard three port audio jack, the digital/ audio signal interface of the present invention not only allows the downloading of software from an external host for upgrading the functionality of a device, such as a telephone butt set, but it eliminates the need for a separate digital port, and thus reduces the aggregate footprint of external connectors, thereby readily contributing to product rniniaturization and environmental sealing. A digital/ audio signal interface for craftperson's butt-in test set is configured to allow either audio signals or serial digital communication signals, such as those associated with the downloading of software for reconfiguring or upgrading the functionality of the test set, to be ported through a standard analog audio jack. The interface includes a controlled connectivity digital signal transport path coupled between the audio jack and digital processor circuitry of the butt set. During a selected communication mode (audio or digital), the interface is operative to decouple the audio jack from test set circuitry associated with the other signal type (digital/ audio).

Claims: CLAIMS 1. A method of interfacing digital communication signals with digital circuitry associated with control of a utility device, said utility device preferably constituted by a telephone butt set having a multiport audio jack through which analog audio signals are ported over an audio signal transport path with audio circuitry of said utility device, said method characterized by the steps of: (a) providing a controlled connectivity digital signal transport path between said audio jack and said digital circuitry of said utility device; and (b) in association with the application to said audio jack of digital communication signals to be coupled to said digital circuitry of said utility device, enabling transport connectivity therefor over said digital signal transport path between said audio jack and said digital circuitry of said utility device, while effectively inhibiting the transport of analog signals over said audio signal transport path with said audio circuitry of said utility device. 2. A method as claimed in to claim 1, characterized by said digital circuitry comprises digital processor circuitry that controls the operation of said utility device, and said digital signals are associated with a modification or replacement of said operating software employed by said digital processor circuitry of said utility device. 3. A method as claimed in claim 1, characterized by said audio signal transport path comprises a controlled connectivity audio signal transport path, and wherein step (b) comprises selectively interrupting connectivity over said controlled connectivity audio signal transport path, and enabling transport connectivity over said controlled connectivity digital signal transport path. 4. A method as claimed in claim 4, characterized by said controlled connectivity audio signal transport path and said controlled connectivity digital signal transport path are provided by way of respective switched audio and digital signal transport paths between signal ports of said audio jack and said audio circuitry and said digital circuitry of said utility device, and step (b) comprises selectively opening said switched audio signal transport path, while closing said switched digital signal transport path, in association with the application to said audio jack of said digital communication signals. 5. A method as claimed in claim 1, characterized by said controlled connectivity audio signal transport path and said controlled connectivity digital signal transport path are provided by way of respective controllably enabled audio and digital amplifier circuits coupled to common signal ports of said audio jack and said audio circuitry and said digital circuitry of said utility device, and wherein step (b) comprises selectively disabling operation of said audio amplifier circuit, while enabling operation of said digital amplifier circuit, in association with the application to said audio jack of said digital communication signal, and in which step (b) also comprises selectively disabling application of power to said audio amplifier circuit, while enabling operation of said digital amplifier circuit. 6. A method as claimed in claim 1, characterized by said controlled connectivity audio signal transport path is provided by way of controllably enabled audio amplifier circuits coupled to input and output signal ports of said audio jack, and said controlled connectivity digital signal transport path is provided by way of controllably enabled digital circuits coupled to a common signal port of said audio jack, and step (b) comprises selectively disabling operation of said audio amplifier circuits, while enabling half-duplex operation of said digital circuits, in association with the application to said audio jack of said digital communication signals. 7. A signal interface for interfacing digital communication signals with digital circuitry associated with operation of a utility device, said utility device having a multiport audio jack through which analog audio signals are ported over an audio signal transport path with audio circuitry of said utility device, characterized by a controlled connectivity digital signal transport path coupled between said audio jack and said digital circuitry of said utility device, and a control circuit, coupled to each of said audio and digital signal transport paths and being operative, in association with the application to said audio jack of digital communication signals, to enable transport connectivity therefor over said digital signal transport path between said audio jack and said digital circuitry of said utility device, while effectively inhibiting transport of analog signals over said audio signal transport path with said audio circuitry of said utility device. 8. A signal interface according to claim 7, characterized by said digital circuitry comprises digital processor circuitry that controls the operation of said utility device, and said digital signals are associated with a modification or replacement of said operating software employed by said digital processor circuitry of said utility device. 9. A signal interface as claimed in claim 7, characterized by said audio signal transport path comprises a controlled connectivity audio signal transport path, and wherein said control circuit is operative to selectively interrupt connectivity over said controlled connectivity audio signal transport path, and enable transport connectivity over said controlled connectivity digital signal transport path. 10. A signal interface as claimed in claim 9, characterized by said controlled connectivity audio signal transport path and said controlled connectivity digital signal transport path comprise of respective switched audio and digital signal transport paths coupled between signal ports of said audio jack and said audio circuitry and said digital processor circuitry of said communication device, and wherein said control circuit is operative to selectively open said switched audio signal transport path and close said switched digital signal transport path, in association with the application to said audio jack of said digital signals associated with a modification or replacement of said operating software employed by said digital processor circuitry of said communication device. 11. A signal interface as claimed in claim 7, characterized by said controlled connectivity audio signal transport path and said controlled connectivity digital signal transport path comprise of respective controllably enabled audio and digital amplifier circuits coupled to common signal ports of said audio jack and said audio circuitry and said digital processor circuitry of said communication device, and wherein said control circuit is operative to selectively disable operation of said audio amplifier circuit, and enable operation of said digital amplifier circuit, in association with the application to said audio jack of said digital signals associated with a modification or replacement of said operating software employed by said digital processor circuitry of said communication device. In which said control circuit is operative to selectively disable application of power to said audio amplifier circuit, while enabling operation of said digital amplifier circuit. 12. A signal interface as claimed in claim 7, characterized by said controlled connectivity audio signal transport path includes controllably enabled audio amplifier circuits coupled to input and output signal ports of said audio jack, said controlled connectivity digital signal transport path includes controllably enabled digital circuits coupled to a common signal port of said audio jack, and said control circuit is operative to selectively disable operation of said audio amplifier circuits, and enable half-duplex operation of said digital circuits, in association with the application to said audio jack of said digital signals associated with a modification or replacement of said operating software employed by said digital processor circuitry of said communication device. 13. A signal interface for upgrading operating software employed by digital processor circuitry that controls the operation of a communication device having a multiport audio jack through which analog signals are ported over an audio signal transport path with audio circuitry of said communication device, characterized by a controlled connectivity digital signal transport path coupled between said audio jack and said digital processor circuitry of said communication device; and a control circuit, coupled to each of said audio and digital signal transport paths and being operative, in association with the application to said audio jack of digital signals associated with a modification or replacement of said operating software employed by said digital processor circuitry of said communication device, to enable transport connectivity therefor over said digital signal transport path between said audio jack and said digital processor circuitry of said communication device, while effectively inhibiting transport of analog signals over said audio signal transport path with said audio circuitry of said communication device.

Inventors: WONG WAYNE, WONG, WAYNE
Applicants: HARRIS CORP, HARRIS CORPORATION
Application year: 2001
Main classification: H04M1
IPC codes: G06F9, H04M1, H04M3