Abstract: A diode-configured power supply interface circuit prevents inadvertent miswiring of power supply leads to wrong polarity voltages of either primary or auxiliary DC supply voltages from triggering the operation of a circuit protection device installed in the power supply path of a telecommunication circuit. It also indicates whether the device's power terminals are properly connected to a power source, so that if inadvertently reversed, the wires can be properly reconnected, and thereby provide for delivery of power from either power source, as required.

Abstract: A diode-configured power supply interface circuit prevents inadvertent miswiring of power supply leads to wrong polarity voltages of either primary or auxiliary DC supply voltages from triggering the operation of a circuit protection device installed in the power supply path of a telecommunication circuit. It also indicates whether the device's power terminals are properly connected to a power source, so that if inadvertently reversed, the wires can be properly reconnected, and thereby provide for delivery of power from either power source, as required.

Abstract: An integrated services digital network (ISDN) test set includes an ISDN transceiver, a supervisory control processor which is operative to cause the ISDN transceiver to controllably transmit and receive ISDN communication messages over a communication circuit, and an alpha-numeric message display through which messages associated with the operation of the ISDN test set are displayed. The test set keypad also includes a dedicated ‘ASSIST’ key, that is selectably operated by the user, to cause the control processor to execute a user assistance routine, which accesses a contextual-based alpha-numeric database, whose contents are associated with and provide additional information of a displayed alpha-numeric message. This enables a test set user, regardless of training or experience, to be provided with information necessary to competently operate the test set and successfully test an ISDN line.

Abstract: A portable ISDN test set contains test circuitry that is controllably operative to automatically test the ISDN communication capability of an ISDN circuit. In response to a user operating a prescribed input/output element of a user interface of the test set, the test set's supervisory control processor executes a routine that places an ISDN call over a first bearer channel of the ISDN circuit, the first bearer channel having a first directory number, through a public switched telephone network to a second directory number associated with a second bearer channel of the ISDN circuit. The ISDN call is thus routed by the public switched telephone network back to the ISDN test set. When the ISDN call is received by the test set, it is automatically looped to the public switched telephone network, so that the call is rerouted to the first directory number associated with the first bearer channel to the ISDN test set.

Abstract: A device and method for testing a telephone circuit in which a caller takes advantage of available caller identification information to complete a ringback test without resort to potentially costly and overused toll trunks. The ringback test device is accessed by a caller (subscriber or craftsperson) who may not be aware of the telephone number from which he is calling when the caller completes a call to a telephone number assigned to the device. As the caller is accessing the test device, the test device detects the caller identification available between the first and second rings to identify the caller's telephone number, and answers the call after the second ring. The test device presents the telephone number to the caller, and the test device may thereafter be used to complete a ringback test to the identified telephone number. The caller ID information may also be display-formatted at the test device and provided to a caller's visual display.

Abstract: A portable ISDN test set contains test circuitry that is controllably operative to automatically test the ISDN communication capability of an ISDN circuit. In response to a user operating a prescribed input/output element of a user interface of the test set, the test set's supervisory control processor executes a routine that places an ISDN call over a first bearer channel of the ISDN circuit, the first bearer channel having a first directory number, through a public switched telephone network to a second directory number associated with a second bearer channel of the ISDN circuit. The ISDN call is thus routed by the public switched telephone network back to the ISDN test set. When the ISDN call is received by the test set, it is automatically looped to the public switched telephone network, so that the call is rerouted to the first directory number associated with the first bearer channel to the ISDN test set.

Abstract: A test set interface automatically determines the type of communication link to which it is coupled, and then configures internal test circuitry to support testing of that particular type of line, irrespective of which of a plurality of different types of communication signals the line may be conveying. The interface includes a multiconductor line cord, end connections of which are configured for connection with any of multiple types of telecommunication circuits. A telecommunication circuit analysis is coupled to the line cord and to test circuitry, and is operative to analyze electrical characteristics of a respective telecommunication circuit to which the line cord is selectively connected by a test set microcontroller, so as to determine which of the different types of communication signals is being conveyed by the telecommunication circuit.

Abstract: A variable geometry battery compartment of an electronic communication device, such as a telephone test set, is readily reconfigurable by the user, so that different sized batteries can be used to power the circuitry of the device. For this purpose, a moveable battery contact wall is repositionable between spaced apart locations relative to a fixed battery contact wall. A charging switch controls the establishment of a charging path for rechargeable batteries, and can only be engaged when the moveable wall is positioned to accommodate longer sized rechargeable batteries. Changing the position of the moveable battery contact wall to accommodate shorter, non-rechargeable batteries, will prevent the charging switch from being engaged by an activating boss in a cover of the device, so that shorter non-rechargeable batteries cannot be placed in circuit with a battery charger.

Abstract: A strain relief attachment for attaching a telephone communication cord to a telephone test set has a line cord strain relief element, a grooved neck end of which is insertable through a tunnel through an end of the test set to a strain relief engagement cavity adjacent to a battery compartment of the test set and accessible by a battery door. The strain relief element includes a bore through which the line cord extends and a flange configured to conform with an external surface of the test set adjacent to the tunnel. The strain relief element engagement cavity is connected by a line cord passageway to the battery compartment. A wedge-shaped line cord retention plug is inserted into the strain relief engagement cavity, engaging the grooved neck of the line cord strain relief element and a wall surface of the strain relief engagement cavity.

Abstract: A test device and a method of testing are provided for an integrated services digital network (ISDN) system having a Network Terminator (NT), a system/terminal (S/T) interface for coupling the NT to a Terminal Equipment (TE), a transmit line between the S/T interface and the NT to permit a TE coupled to the S/T interface to transmit D channel and B channel information to the NT, and a receive line coupled between the NT and S/T interface to permit a TE coupled to the S/T interface to receive D channel and B channel information from the NT. The test device performs an initial line connection test to determine if a satisfactory line connection exists between the NT and the S/T interface connected by the transmit and receive lines by providing a predetermined signal to the NT from the test device and for evaluating a response from the NT to the predetermined signal.