Telephone line extender with test thru capability

Claim 2

In a telephone circuit for connecting tip and ring lines from central office switching Equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, relay means including a first set of contacts interposed between the central office tip and ring lines and the input terminals of the line extender as well as a second set of contacts interposed between the output terminals and the subscriber''s telephone set so connected and arranged that when the relay means is actuated, direct connection is made between the corresponding ring and tip lines with the line extender being isolated from the lines.

Claim 3

The combination as claimed in claim 1 in which the sets of contacts associated with the tip and ring lines are each in the form of a double-pole, double-throw switch in which the poles of the switch are connected to the lines and in which one pair of outside switch contacts are connected to the line extender terminals and the other pair of outside contacts are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter.

Claim 4

The combination as claimed in claim 1 in which the relay means is in the form of a relay having contacts arranged in the configuration of two double-pole, double-throw switches.

Claim 5

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, relay means including contacts interposed between the line extender and the tip and ring lines so that when the relay is in one state and the line extender is connected in series with the lines and so that when the relay is in its opposite state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter.

Claim 6

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, relay means including contacts interposed between the line extender and the tip and ring lines so that when the relay is in one state and the line extender is connected in series with the lines and so that when the relay is in its opposite state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter.

Claim 7

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, magnetic relay means including contacts interposed between the terminals of the line extender and the tip and ring lines, the contacts being so connected and arranged that when the relay is in a first state the line extender is connected in series with the lines and so that when the relay is in its opposite state corresponding lines are connected together to form a metallic By-pass around the line extender completely isolated from the terminals of the latter, and a test set for providing a voltage to the magnetic relay for placing the contacts in their by-passing relation incident to the making of tests upon the tip and ring lines leading to the subscriber''s telephone set.

Claim 8

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, magnetic relay means including contacts interposed between the terminals of the line extender and the tip and ring lines, the contacts being so connected and arranged that when the relay is in a first state the line extender is connected in series with the lines and so that when the relay is in its opposite state corresponding lines are connected together to form a metallic By-pass around the line extender completely isolated from the terminals of the latter, and a test set for providing a voltage to the magnetic relay for placing the contacts in their by-passing relation incident to the making of tests upon the tip and ring lines leading to the subscriber''s telephone set.

Claim 9

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, diversion relay means including contacts interposed between the line extender and the tip and ring lines so that when the relay is in its first state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter thereby to provide a direct metallic connection to the subscriber''s telephone set for conducting a ringing signal thereto and so that when the relay is in its opposite state the line extender is connected in series with the lines, and means responsive to the flow of direct current in the lines leading to the subscriber''s telephone set resulting from the subscriber''s lifting the receiver from the hook for placing the diversion relay in its opposite state so that the auxiliary voltage is added to the loop thereby to increase the current flow for more positive subsequent operation of the central office switching equipment.

Claim 10

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of a subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, diversion relay means including contacts interposed between the line extender and the tip and ring lines so that when the relay is in its first state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter thereby to provide a direct metallic connection to the subscriber''s telephone set for conducting a ringing signal thereto and so that when the relay is in its opposite state the line extender is connected in series with the lines, and means responsive to the flow of direct current in the lines leading to the subscriber''s telephone set resulting from the subscriber''s lifting the receiver from the hook for placing the diversion relay in its opposite state so that the auxiliary voltage is added to the loop thereby to increase the current flow for more positive subsequent operation of the central office switching equipment.

Claim 11

The combination as claimed in claim 6 which includes overriding means for causing the relay to revert to its first state for the making of tests upon the tip and ring lines leading to the subscriber''s telephone set.

Claim 12

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of the subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, diversion relay means including contacts interposed between the terminals of the line extender and the tip and ring lines, the contacts being so connected and arranged that when the relay is in a first state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter thereby to provide a direct metallic connection to the subscriber''s telephone set for conducting a ringing signal thereto, the contacts being so arranged that when the relay is in its opposite state the line extender is connected in series with the lines, and means including current detecting relays in the tip and ring lines of the subscriber''s telephone set for responding to the direct current flow resulting from the subscriber''s lifting the receiver from the hook for placing the diversion relay in the opposite state so that the auxiliary voltage is added to the loop thereby to increase the current flow for more positive subsequent operation of the central office switching equipment, the current detecting relays havinG an associated ''''or'''' gate for coupling the same to the diversion relay so that flow of current in either of the current detecting relays is effective to operate the diversion relay.

Claim 13

In a telephone circuit for connecting tip and ring lines from central office switching equipment, including a central office battery, to the tip and ring lines of the subscriber''s telephone set to form a loop circuit, the combination comprising a line extender having a pair of input terminals providing connection to the central office tip and ring lines and a pair of output terminals providing connection to the tip and ring lines of the subscriber''s telephone set, two sources of auxiliary direct voltage in the line extender, means in the line extender for detecting the polarity of the voltage of the central office battery and for automatically connecting one of the sources of auxiliary voltage into the loop in additive relation, diversion relay means including contacts interposed between the terminals of the line extender and the tip and ring lines, the contacts being so connected and arranged that when the relay is in a first state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the terminals of the latter thereby to provide a direct metallic connection to the subscriber''s telephone set for conducting a ringing signal thereto, the contacts being so arranged that when the relay is in its opposite state the line extender is connected in series with the lines, and means including current detecting relays in the tip and ring lines of the subscriber''s telephone set for responding to the direct current flow resulting from the subscriber''s lifting the receiver from the hook for placing the diversion relay in the opposite state so that the auxiliary voltage is added to the loop thereby to increase the current flow for more positive subsequent operation of the central office switching equipment, the current detecting relays havinG an associated ''''or'''' gate for coupling the same to the diversion relay so that flow of current in either of the current detecting relays is effective to operate the diversion relay.

Claim 14

The combination as claimed in claim 8 in which the current detecting relay is in the form of a light emitting diode having a photocell with the photocell being connected in controlling relation to the diversion relay.

Claim 15

The combination as claimed in claim 8 in which means are provided for overridingly placing the diversion relay in its first state for the making of tests upon the subscriber''s tip and ring lines when the subscriber''s receiver is removed from the hook.

Claim 16

The combination as claimed in claim 8 in which means are provided for holding the diversion relay in the state corresponding to conduction in the loop during sudden reversal of polarity of the central office battery.