Trunk busy test circuit

Claim 2

A test circuit for enabling a test position to conduct operational tests on telephone central office trunks arranged to establish subscriber calls between telephone stations comprising means responsive to signals generated by the test position for selecting ones of the trunks, means enabled by the test position for identifying idle and busy ones of the selected trunks, means for distinguishing between ones of the busy trunks handling subscriber calls and ones of the busy trunks made trouble busy, and means for connecting both the selected idle and trouble madebusy trunks with the test position.

Claim 3

The test circuit set forth in claim 1 further comprising make-busy plug apparatus arranged to busy one of the trunks by connecting a make-busy lead of the trunk to ground through a diode.

Claim 4

The test circuit set forth in claim 2 wherein said make-busy plug apparatus comprises a latch relay having a coil winding responsive to current flow in one direction for closing make contacts and responsive to current flow in another direction for releasing said make contacts, a pair of zener diodes connected in series with said latch relay coil winding, and control path means including said make contacts and connected in parallel with said latch relay and said zener diodes for connecting said diode between ground and the trunk make-busy lead.

Claim 5

The test circuit set forth in claim 3 wherein said identifyIng means comprises a first test relay connected to a negative voltage source, means responsive to the test position for operating said first test relay and connecting said operated first test relay to the make-busy lead of the selected trunks, and means enabled by the subsequent release of said first test relay connected to the make-busy lead of a selected one of the trunks for indicating an idle state of the selected trunk to the test position.

Claim 6

The test circuit set forth in claim 4 wherein said distinguishing means comprises a slow-operate relay, a second test relay connected to a positive voltage source, means responsive to the test position for initiating operation of said slow-operate relay and for connecting said second test relay to the make-busy lead of the identified busy trunks, and means responsive to release of said second test relay and the operation of said slow-operate relay for determining that ones of the identified busy trunks having make-busy leads connected to ground through said diode are trouble made-busy trunks.

Claim 7

The test circuit set forth in claim 5 wherein said connecting means comprises means enabled by said operating and connecting means in combination with the release of said first test relay for coupling the test position with the selected idle trunks, and means enabled by the release of said second test relay in combination with operation of said slow-operate relay and said operating and connecting means for coupling the test position with the trouble made-busy trunks.

Claim 8

The test circuit set forth in claim 6 further comprising means enabled by the test position for connecting another negative voltage source to the make-busy lead of a selected trunk equipped with said make-busy plug apparatus to make the selected trunk trouble busy, and means enabled by the test position for connecting another positive voltage source to the make-busy lead of a selected trouble busy trunk equipped with said make-busy plug apparatus to restore the selected trouble busy trunk for use in establishing the subscriber calls.

Claim 9

A test circuit for enabling a test position to conduct operational tests on telephone central office trunks arranged to establish subscriber calls between telephone stations comprising first and second test relays, means responsive to signals generated by the test position for selecting ones of the trunks, means responsive to the test position for operating said first test relay and connecting said operated first test relay to a make-busy lead of the selected trunks, means enabled by the subsequent release of said first test relay connected to the make-busy lead of one of the selected trunks for indicating an idle state of the selected trunk to the test position, means enabled by the test position for connecting said second test relay with the make-busy lead of a selected one of the trunks identified by continued operation of said connected first test relay as busy, means responsive to operate and release states of said connected second test relay for distinguishing between ones of the identified busy trunks handling subscriber calls and ones of the identified busy trunks having been made trouble busy, and means for connecting both the selected idle and made trouble busy trunks with the test position.

Claim 10

A test circuit for enabling a test position to conduct operational tests on telephone central office trunks arranged to establish subscriber calls between telephone stations comprising first and second test relays, means responsive to signals generated by the test position for selecting ones of the trunks, means responsive to the test position for operating said first test relay and connecting said operated first test relay to a make-busy lead of the selected trunks, means enabled by the subsequent release of said first test relay connected to the make-busy lead of one of the selected trunks for indicating an idle state of the selected trunk to the test position, means enabled by the test position for connecting said second test relay with the make-busy lead of a selected one of the trunks identified by continued operation of said connected first test relay as busy, means responsive to operate and release states of said connected second test relay for distinguishing between ones of the identified busy trunks handling subscriber calls and ones of the identified busy trunks having been made trouble busy, and means for connecting both the selected idle and made trouble busy trunks with the test position.

Claim 11

The test circuit set forth in claim 8 further comprising make-busy plug apparatus for connecting the make-busy lead of one of the trunks to ground through a diode comprising a latch relay responsive to current flow in one direction for closing make contacts and responsive to current flow in another direction for releasing said make contacts, a first control path for enabling said latch relay and comprising zener diodes connected in series with said latch relay, and a second control path connected in parallel with said first control path for busying the one trunk and comprising the diode connected in series with said make contacts.

Claim 12

The test circuit set forth in claim 9 further comprising circuitry for remotely controlling said make-busy plug apparatus to remove and restore the one trunk to subscriber service by applying positive and negative voltages to the make-busy lead for the purpose of enabling said latch relay to close and release said make contacts.

Claim 13

A test circuit for use with a remote office test line to enable a test position to conduct operational tests on selected telepone central office idle and busy trunks comprising test apparatus for distinguishing ones of the selected busy trunks handling subscriber calls from ones of the selected busy trunks made trouble busy, path connect apparatus for connecting the selected idle trunks and the selected made trouble busy trunks with the test position, and make-busy plug apparatus controllable from the test position for placing the selected idle trunks in a trouble busy state and the selected trouble busy trunks in an idle state.

Claim 14

A test circuit for use with a remote office test line to enable a test position to conduct operational tests on selected telepone central office idle and busy trunks comprising test apparatus for distinguishing ones of the selected busy trunks handling subscriber calls from ones of the selected busy trunks made trouble busy, path connect apparatus for connecting the selected idle trunks and the selected made trouble busy trunks with the test position, and make-busy plug apparatus controllable from the test position for placing the selected idle trunks in a trouble busy state and the selected trouble busy trunks in an idle state.