Remote testing system for communication circuits

Claim 2

A test trunk circuit for completing, maintaining and disconnecting test connections between a distant test center and local test circuits for remote testing of subscriber communication lines comprising: a. connection means for connecting said test trunk circuit to a set of local line circuit terminals of a central office switching system; b. a tone signal source; c. timing means adapted to connect said tone signal source to said connection means after a lapse of several seconds following activation of said timing means; d. acknowledgemEnt means adapted, in response to a ringing current received over said connection means: i. to trip further transmission of ringing current, ii. to connect said tone signal source to said connection means for a short period of the order of 1 second, iii. to interrupt during said short period a connection between said connecting means and said local test circuits and establish said connection at the end of said short period and iv. to activate said timing means; e. holding means adapted, in response to a predetermined answer signal tone received over said connection means, to block the operation of said timing means and f. disconnecting means adapted, in response to a predetermined disconnect signal tone, to restore the entire test trunk circuit to its idle state, said disconnecting means being further adapted to do the same also in response to a disconnection requesting condition communicated to said connection means by said central office switching system.

Claim 3

A test trunk circuit as defined in claim 1 which comprises also: g. a second timing means and h. reset means adapted, in response to the presence of any testing signal in said local test circuits, to supply a reset condition for at least a predetermined short period and in which: i. said acknowledgement means is further adapted to activate said second timing means, j. said holding means is further adapted, in response to said answer signal tone, to prepare said second timing means to be reset by the occurrence of said reset condition and k. said second timing means is adapted to operate said disconnecting means after a predetermined period of at least half a minute following the activation of said second timing means unless during said predetermined period said reset condition occurs while said second timing means is prepared by said holding means for responding to said reset condition, said second timing means being also adapted to be freshly activated by said reset condition to start a new timing cycle when said reset condition ends.

Claim 4

A test trunk circuit as defined in claim 1 in which the first mentioned timing means is further adapted to interrupt the said connection between said connecting means and said local test circuit while said tone signal source is connected to said connection means.

Claim 5

In combination in a system for remote testing of subscriber communication lines: a. a test trunk circuit as defined in claim 1; b. a test position having i. a telephone and calling circuit, ii. test center remote testing circuits and iii. a remote testing trunk circuit connected to a set of local line terminals of a second central office switching system and adapted to transmit tone signals from said test center remote testing signals to said switching system and vice versa, and c. switch-controlled means also at said test position for either i. connecting said telephone and calling circuit to said set of local line terminals over a path that bypasses facilities of said remote testing trunk circuit while disconnecting therefrom said test center remote testing circuits to enable a connection to said first-mentioned test trunk circuit to be made under control of said telephone and calling circuit, or (in another position of said switch controlled means) ii. disconnecting said telephone and calling circuit and said path from said remote testing trunk circuit and from each other and connecting said test center remote testing circuits to said remote testing trunk circuit after said connection to said first-mentioned test trunk is made, d. whereby said local test circuits for remote testing of subscriber communication lines may be operated from test center and test results observed at said test center over the same non-dedicated communication facilities joining said central office switching systems as are used for making said connection to said first-mentioned test trunk circuit.

Claim 6

A combination as defined in clAim 4 in which said switch controlled means, when actuated to disconnect said telephone and calling circuit as aforesaid, is arranged to cause transmission to said remote testing trunk circuit a predetermined answer tone signal to activate said holding means thereof.