Telephone test set
First Claim
Patent Images
1. A telephone test set comprising:
- (a) a first lead and a second lead which are respectively adapted to be connected to a tip line and a ring line of a telephone line;
(b) a full wave rectifying means for providing a rectified output of an input signal and having a pair of input terminals which are respectively connected to the first lead and the second lead and a pair of output terminals which respectively output a voltage of a first polarity and a second polarity;
(c) a shunt circuit coupled between the pair of input terminals of the full wave rectifying means which is comprised of a series connection of a means for transmitting and receiving voice communications and a switching means having an open circuit condition when a control signal of a first magnitude is applied to a control terminal and having a closed circuit condition when the control signal of a second magnitude is applied to the control terminal to permit current to flow within the shunt circuit;
(d) a signaling means coupled between the pair of output terminals for producing signals to place a telephone call over the tip and ring lines to a central office when in an activated state and for not producing signals when in an inactive state, and(e) control means responsive to the signaling means for producing the control signal having the first magnitude when the signaling means for placing a telephone call is in the active state and having the second magnitude when the signaling means for placing a telephone call is in the inactive state.
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Abstract
An improved telephone test set is disclosed which may be operated with low voltage line conditions. Transmitting and receiving voice communication circuits are connected in parallel with leads which are adapted to be connected to the tip and ring lines of a subscriber'"'"'s telephone line to isolate the voice transmitting and receiving circuits from the voltage drop of a polarity guarding bridge which is connected to the signalling circuits of the telephone test set. A polarity indicating circuit to indicate the direction of current flow between the tip and ring lines of a subscriber'"'"'s telephone line is connected in series with the voice transmitting and receiving circuits.
14 Citations
25 Claims
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1. A telephone test set comprising:
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(a) a first lead and a second lead which are respectively adapted to be connected to a tip line and a ring line of a telephone line; (b) a full wave rectifying means for providing a rectified output of an input signal and having a pair of input terminals which are respectively connected to the first lead and the second lead and a pair of output terminals which respectively output a voltage of a first polarity and a second polarity; (c) a shunt circuit coupled between the pair of input terminals of the full wave rectifying means which is comprised of a series connection of a means for transmitting and receiving voice communications and a switching means having an open circuit condition when a control signal of a first magnitude is applied to a control terminal and having a closed circuit condition when the control signal of a second magnitude is applied to the control terminal to permit current to flow within the shunt circuit; (d) a signaling means coupled between the pair of output terminals for producing signals to place a telephone call over the tip and ring lines to a central office when in an activated state and for not producing signals when in an inactive state, and (e) control means responsive to the signaling means for producing the control signal having the first magnitude when the signaling means for placing a telephone call is in the active state and having the second magnitude when the signaling means for placing a telephone call is in the inactive state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An indicating circuit within a telephone test set for continuously signaling the direction of current flow between tip and ring lines of a telephone line in which the indicating circuit is connected in series with a means for transmitting and receiving voice communications within the test set comprising:
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(a) a pair of oppositely poled light emitting diodes for respectively indicating different directions of current flow between the tip and ring lines by emitting light of a different color, the pair of oppositely poled diodes being coupled between one of the lines of the telephone line and the means for transmitting and receiving; (b) an audio frequency bypass means which shunts the oppositely poled light emitting diodes to permit audio frequencies to bypass the light emitting diodes; and (c) a resistance which shunts the oppositely poled light emitting diodes to permit conduction of current in the shunt circuit when a voltage across the oppositely poled light emitting diodes is insufficient to bias one of the light emitting diodes substantially into conduction. - View Dependent Claims (22, 23)
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24. A telephone test set comprising:
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(a) a first lead and a second lead which are respectively adapted to be connected to a tip line and a ring line of a telephone line; (b) a shunt circuit coupled between the first lead and the second lead which is comprised of a series connection of means for transmitting and receiving voice communications and a switching means having an open circuit condition when control signal of a first magnitude is applied to a control terminal and having a closed circuit condition when the control signal of a second magnitude is applied to the control terminal to permit current to flow within the shunt circuit; (c) a signaling means coupled to the first and second leads for producing signals to place a telephone call over the tip and ring lines to a central office when in an activated state and for not producing signals when in an inactive state, the signaling means not being coupled in series within the shunt circuit; (d) means for providing electrical power to the signaling means; and (e) control means responsive to the signaling means for producing the control signal having the first magnitude when the signaling means for placing a telephone call is in the active state and having the second magnitude when the signaling means for placing a telephone call is in the inactive state. - View Dependent Claims (25)
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Specification