Telephone test instrument

Details Telephone test instrument Telephone test instrument

1990-03-13

1991-06-18

Schreyer, Stafford D.

Telephonic communications

Diagnostic testing, malfunction indication, or electrical...

Of data transmission

379 21, H04M 102, H04M 124, H04M 1900

Patent

active

050254669

ABSTRACT:
A telephone test instrument permits voice communications with and monitoring of a telephone circuit to be tested. The instrument includes a microprocessor used in controlling various functions of the instrument. The microprocessor and other circuits of the instrument are energized from a connected telephone circuit and/or an internal energy supply which is automatically recharged from the telephone circuit. The microprocessor continually checks the voltage of the internal energy supply and automatically turns off a loudspeaker of the instrument, or prevents it from being turned on, if the voltage is too low. The instrument includes circuitry which, in combination with the microprocessor, measures loop current or line voltage while the instrument is connected for making voice communications with the telephone circuit. When the loudspeaker within the instrument is energized, the earpiece receiver remains active. A belt hook connected to a housing of the instrument can connect an electrical ground through a switch in the instrument to the telephone circuit for providing a ground start. The instrument also includes a "crow-bar" circuit which effectively open-circuits the instrument from a connected telephone circuit if too high of a loop current flows.

REFERENCES:
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CMC publication entitled "CMC 7900 Butt-In II Test Set" published at least one year prior to Jan. 1990, labeled Exhibit 1.
Harris Corporation publication introducing the test set with a built-in amplified speaker published at least one year prior to Jan. 1990, labeled Exhibit 2.
AT&T publication entitled "Craft Access Terminal" dated Jun. 1985 and labeled Exhibit 3.
Telephony publication entitled "Powerful new tool makes field craft more self-reliant", dated Sep. 2, 1985 and labeled Exhibit 4.
Telephone Engineer & Management article entitled "Tiny terminal ties telco team" dated Jul. 1, 1986 and labeled Exhibit 5.
Necsy catalog page entitled "Operating Instructions" dated 2/20/1988 and labeled Exhibit 6.
Ziad Inc. publication entitled "The PHD.TM. Telecommunicator-More Than Just An Educated Guess" dated Jun. 1985 and labeled Exhibit 7.
Ziad Inc. publication entitled "Introducing Line Master.TM.", published at least one year prior to Jan. 1990 and labeled Exhibit 8.
Nicollet Technologies, Inc. entitled "Introducing the DigiSmart.TM. 4000-R" dated 1987 and labeled Exhibit 9.

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