Abstract:
A cordless telephone headset and remotely controlled telephone handset pick-up device for use in conjunction with an existing corded telephone set. A mechanical lift arm of the pick-up device, driven by an electric motor with a slip clutch, lifts the handset away from the corded telephone cradle, placing the telephone handset in an off-hook position. The handset is lowered back onto the cradle by the mechanical lift arm, returning the telephone set to an on-hook position. The mechanical lift arm is activated and deactivated in response to a radio signal indicative of the lowering and raising of the microphone boom of the cordless headset. The slip clutch provides sufficient force to gently and reliably raise and lower the telephone handset without causing misalignment between the handset and the cradle and without causing damage. As the handset is gently lowered over the hook switch, the motor drives the lift arm downward beyond a point at which the handset is expected to be lowered into the cradle, ensuring that the telephone is reliably placed on-hook, while the slip clutch limits the amount of force that can be applied to the telephone set. The telephone set rests upon a platform coupled to the lift-arm, providing a unitary structure for the telephone set and handset pick-up device which aids in maintaining proper alignment of the handset to the cradle by preventing the lift arm from forcing the pick-up device out alignment.

Description:
RELATED APPLICATIONS 
     This application is a continuation application of application Ser. No. 08/798,372 filed Feb. 10, 1997 now U.S. Pat. No. 6,081,596 and claims priority therefrom. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the field of telephones. More particularly, this invention relates to the field of automatic telephone handset pick-up devices. 
     BACKGROUND OF THE INVENTION 
     Since the advent of the telephone, a variety of accessories have been developed for making telephone usage more convenient and for meeting various needs of telephone users. Among these accessories are cordless telephones. Cordless telephones generally include a base unit and a cordless handset or a headset. The base unit is typically coupled to a telephone wall jack or to an existing corded telephone set and includes a radio transceiver for transmitting and receiving signals between the base unit and the handset or headset. 
     Contemporary cordless handsets offer users most, if not all, of the operational features currently associated with conventional corded telephones. This includes notification of an incoming call, an ability to answer the call, to initiate a call, dial a number, to converse with the other party, and to terminate the call by hanging-up. This allows a user to rely solely on the cordless handset for all operational features of the telephone. Cordless handsets, however, like corded handsets, require that the user occupy one hand with the handset or require that the user cradle the handset between the user&#39;s shoulder and ear. 
     Cordless telephone headsets have emerged as another popular telephone accessory. The cordless headset is worn by the user and typically incorporates a microphone boom, a microphone, a speaker and a transceiver housed within the headset which allow the headset to communicate directly with a base unit. As such, cordless headsets allow the user to converse with another party while having both hands free and while having freedom of movement within the range of the transceiver. 
     Headsets, cordless and corded, however, only replace the functionality of a handset and do not include all the functions of a telephone. For example, headsets are generally not configured to initiate a call, to dial a number or to answer an incoming call. As such, cordless headsets typically do not provide an ability to control the base unit to go off-hook for receiving an incoming call or to go on-hook to hang-up the call at the end of a conversation. Thus, their utility is limited in that the user must be stationed near the existing corded telephone set to answer an incoming call. Only after the call has been answered can the user walk freely away while continuing the conversation. The user must again return to the existing corded telephone set to terminate the call by hanging up. 
     Cordless headsets are often provided as an after-market add-on for an existing telephone. As such, a cordless headset from one source or manufacturer can generally be used with telephones from a variety of sources or manufacturers. An example of a prior art cordless headset  100  is illustrated in FIG.  1 . Headsets identical or similar to the headset  100  can be obtained from Hello Direct, Inc, located at 5893 Rue Ferrari, in San Jose, Calif. or by calling Hello Direct, Inc. at 1(800)444-3556. 
     The headset  100  includes a microphone  101 , a receiver speaker  102  and a transceiver  103 . The headset  100  is designed to allow hands free telephone conversations once a call is established. The headset  100  communicates via radio frequency signals with a base unit  104  which is coupled to the handset port of an existing telephone  105 . A battery powered radio transceiver  103  is included in the headset  100 . In operation, battery power is removed from the headset  100  when the microphone boom  106  is rotated upwards such that it is approximately perpendicular to the ground. When the boom  106  is rotated downward, battery power is applied to the headset  100  such that the user is able to converse with another party over the telephone. The headset  100  is designed so that it can be configured for use with an existing telephone  105 . Thus, to install the base unit  104 , the base unit  104  is electrically coupled to the telephone handset port. The handset  107  is disconnected from the handset port of the telephone  105  and reconnected to an appropriate port of the base unit  104 . The headset  100  and the handset  107  can be used interchangeably, but not at the same time. 
     To place or answer a call, the user must remove the handset  107  from the cradle  108 . FIGS. 2 and 3 illustrate a prior art device for mechanically raising a telephone handset off-hook The device illustrated in FIGS. 2 and 3 is currently available from Hello Direct, Inc., under the name TOUCH-N-TALK™ and is the subject of U.S. Pat. No. D358,594. By rotating a lever  201 , a bar  202  engages the handset  107  and lifts the handset  107  from the cradle  108 , thus placing the telephone off-hook. Rotating the lever  201  in the opposite direction replaces the handset  107  on the cradle  108 , placing the telephone on-hook. Therefore, this device allows a user to manually answer and hang-up calls without having to fully remove the handset  107  from the cradle  108 . The device illustrated in FIGS. 2 and 3 has a drawback in that the user must be in a position to manually lift the handset from the cradle in order to answer and to terminate a call. 
     FIG. 4 illustrates a prior art hook switch On/Off device described in European Patent Application No. EP 680,188. When an On/Off control signal is applied to a XOR gate  401 , a driving motor  401  starts rotation of gears  402 ,  403  and semi-circular gear  404 . Rotation of the gear  404  causes a member  104   b  to rise relative to a member  405 , lifting a telephone handset from its hook switch. When the separating member  104   b  rises sufficiently, a sensor  407  signals the motor  401  to stop. When the On/Off control signal indicates the call is over, the motor  401  rotates the gear  404  until the gear  404  no longer engages the member  104   b .This causes the member  104   b  to fall, dropping the handset onto the hook switch. The sensor  407  then signals the motor  401  to stop. This device has a drawback in that repeatedly dropping the telephone handset onto the hook switch of the telephone may eventually damage the handset, the hook switch or the telephone. In addition, the handset may become misaligned from the member  104   b  or from the cradle such that the handset may not land directly on the hook switch, causing the hook switch to remain off hook. Failure to properly hang up after a telephone call can result in unnecessary telephone charges, while later callers can receive a busy signal. Also, the linear lift mechanism and mechanical configuration of the commercial embodiment of this device allow it to be readily configured to only a limited number of commercially available telephone sets. 
     What is needed is a device that will notify a headset user of an incoming call and that will allow the user to reliably answer calls and to hang-up the calls from a remote location using the cordless headset. What is further needed is a device of the aforementioned type that is compatible with existing telephone units. 
     SUMMARY OF THE INVENTION 
     The invention is a cordless telephone headset and remotely controlled telephone handset pick-up device adapted for use in conjunction with an existing corded telephone set. A base unit is electrically coupled to the handset port of the corded telephone, while the handset of the corded telephone is electrically coupled to the base unit. The base unit communicates with the headset via radio signals. A mechanical lift arm of the pick-up device, driven by an electric motor with a slip clutch, lifts the handset away from the corded telephone cradle, placing the telephone handset in an off-hook position. From the off-hook position, the handset is lowered back down onto the cradle by the mechanical lift arm, returning the telephone set to arivn-hook position. The mechanical lift arm is activated and deactivated in response to a radio signal indicative of the lowering and raising of the microphone boom of the cordless headset. 
     The slip clutch provides sufficient force to gently and reliably raise and lower the telephone handset without causing misalignment between the handset and the cradle and without causing damage to the handset, the hook switch or to the telephone set. As the handset is gently lowered over the hook switch, the motor drives the lift arm downward beyond a point at which the handset is expected to be lowered into the cradle to ensure that the telephone is reliably placed on-hook, while the slip clutch limits the amount of force that can be applied to the telephone set. In other words, the duration of time the device lowers the handset is longer than for raising the handset to ensure that the handset is fully replace on the cradle. 
     The telephone set rests upon a platform coupled to the lift-arm. This arrangement provides a unitary structure for the telephone set and handset pick-up device which aids in maintaining proper alignment of the handset to the cradle by preventing the lift arm from forcing the pick-up device out alignment when the lift arm picks up the handset and when the clutch slips against the telephone. The lift arm rotates about a pivoting axis. The length of the arm is variable to accommodate a variety of telephone configurations. Additionally, the use of this unitary structure in combination with the rotating lift arm allow this device to be used with a very wide variety of commercially available telephone sets. 
     A microphone and a sensor are positioned to sense when the corded telephone is ringing. When it is determined that the corded telephone is ringing, a signal is transmitted to the cordless headset to alert the user of the incoming call. To answer the call from the cordless headset, the user lowers the microphone boom of the headset into an in-use position, thereby causing the headset to signal the base unit to go off-hook. The base unit then causes the mechanical lift arm to raise the handset from its cradle. When the handset is raised from the cradle, the telephone is off-hook and the incoming call is coupled to the cordless headset. The user can then converse with the caller. To terminate the call, the user raises the microphone boom of the headset into a standby position, thereby causing the headset to signal the base unit to go on-hook, causing the mechanical lift arm to lower the handset back into the cradle, terminating the call. When the handset is in the cradle, the telephone is on:hook and is again ready to accept incoming calls. 
     In this manner, incoming calls can be reliably answered and terminated using the cordless headset, even when the user is at a remote location away from the corded telephone set. If desired, the handset of the corded telephone can be used to communicate over the telephone line when the user is located near the corded telephone set. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a prior art headset system coupled to a conventional telephone. 
     FIG. 2 illustrates a prior art mechanical device for raising a telephone handset off-hook. 
     FIG. 3 illustrates the prior art device illustrated in FIG. 2 coupled to a conventional telephone. 
     FIG. 4 illustrates a prior art hook switch On/Off device. 
     FIG. 5 illustrates a perspective view of the present invention. 
     FIG. 6 illustrates a side view of the present invention. 
     FIG. 7 illustrates a detailed schematic of the motor control circuit. 
     FIG. 8 illustrates a detailed schematic of the motor control circuit and the microphone preamplifier circuit 
     FIG. 9 illustrates a block diagram for the present invention. 
     FIG. 10 shows a schematic representation of a headset and controller according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 5 illustrates a perspective view of the present invention. A main stand  10  and an outer stand  11  comprise a platform  17  of the invention. The platform  17  is designed to have a corded telephone unit (not shown) rest on top of the platform  17  to ensure that the corded telephone will remain correctly positioned relative to the present invention. Further, with the corded telephone unit resting on top of the platform  17 , the present invention and the corded telephone unit are coupled together such that they act as a single structural unit. 
     The main stand  10  and the outer stand  11  are preferably separable. Multiple outer stands  11  can be coupled to this construction to accommodate wider telephone sets. It will be apparent, however, that other means can be provided for adjusting the size of the platform  17 . 
     A pedestal unit  12  is coupled to the platform  17 . A microphone  14  is coupled to the pedestal unit  12 . The pedestal unit  12  offers structural support for a motor housing  13  and also serves as a housing for control circuits. A handset shaft  16  is coupled between a drive shaft  18  and a handset arm  15 . Together, the handset shaft  16  and handset arm  15  comprise a lift-arm  19 . The length of the lift-arm  19  is adjustable to be variable which allows the present invention to accommodate a variety of telephone configurations. The handset arm  15  can be padded to protect the corded telephone handset (not shown). Preferably, the padding also prevents the handset from shifting its position relative to the lift-arm  19  at times when the handset is lifted by the lift-arm  19 . 
     FIG. 6 illustrates a side cut-away view of the present invention which highlights elements of the pedestal unit  12 . The drive shaft  18  is surrounded by motor shaft bushings  20 . The motor shaft bushings  20  keep the handset shaft  16  properly aligned. A clutch housing  21  contains a clutch band mechanism  22 . The clutch band mechanism  22  is coupled to the drive shaft  20  and the handset shaft  16 . The clutch band mechanism transfers the energy from the motor  27  to the drive shaft  18 . The amount for force that the motor  27  can apply to the drive shaft  18  is selectively limited by the amount of force generated by the clutch band mechanism  22 . Accordingly, the clutch band mechanism  22  prevents the motor  27  from over-straining when the handset shaft  16  has reached a furthermost downward position or when the handset shaft  16  contacts an unexpected obstacle while the motor is still running. 
     A height adjustable potentiometer  26  allows the user to adjust the pick up height that the present invention lifts the corded telephone handset. The height adjustability makes the invention easily adaptable to a wide variety of corded phones. By minimizing the height to which the handset is lifted, the opportunity for misalignment of the handset to the telephone hook switch will be reduced as the handset will be less likely to shift its position relative to the handset arm  15 . A PC board  23  houses the circuitry for detecting a ring and controlling the motor  27 . A microphone input  25  provides the present invention with a telephone ring detection input signal and is coupled to the PC board  23 . The port  24  provides the signal to the cordless headset and likewise, receives a signal from the cordless headset. The port  24  serves as the communications port which links the present invention to the cordless headset. 
     FIG. 7 illustrates a detailed schematic of a circuit for controlling the motor which is implemented on the PC board  23  of FIG.  6 . It will be apparent that other circuits can be readily designed and implemented to control the motor. A logic input is entered on line  100 . Line  100  is coupled to a first terminal of a resistor  101  (100 k ohms), a first terminal of a switch  102 , and a first terminal of a resistor  104  (100 k ohms). A second terminal of the resistor  101  is coupled to the ground. A second terminal of the switch  102  is coupled to a first terminal of a resistor  103  (100 k ohms). A second terminal of the resistor  104  is coupled to a base terminal of an npn transistor  105  (2N4401). An emitter terminal of the transistor  105  is coupled to the ground. A collector terminal of the transistor  105  is coupled to a second terminal of the resistor  103 , an input terminal of an inverter  106  (4049), and an input terminal of an inverter  134  (4049). 
     An output terminal of the inverter  106  is coupled to an input terminal of an inverter  107  (4049). An output terminal of the inverter  107  is coupled to a first terminal of a resistor  108  (10 k ohms). A second terminal of the resistor  108  is coupled to a first terminal of a capacitor  110  (0.1 μF ) and a collector terminal of an npn transistor  122  (2N4401). A second terminal of the capacitor  110  is coupled to an input terminal of an inverter  111  (4049) and a first terminal of a resistor  109  (1M ohms). A second terminal of the resistor  109  and an emitter terminal of the transistor  122  are coupled to the ground. An output terminal of the inverter  111  is coupled to a first terminal of a resistor  112  (10 k ohns) and pin  8  of a chip  113 . 
     The chip  113  is preferably part number LH556 and provides the circuit in the FIG. 7 with proper control signals to operate the motor  126 . It will be apparent that other motor control circuits can be utilized. Pin  9  of the chip  113  is coupled to an anode terminal of a diode  121  (1N4140). Pin  10  of the chip  113  is coupled to the power supply VCC. Pin  11  of the chip  113  is coupled to a positive terminal of a capacitor  114  (0.1 μF), and a negative terminal of the capacitor  114  is coupled to the ground. Pins  12  and  13  of the chip  113  are coupled to a positive terminal of the capacitor  116  and a first terminal of a variable resistor  115 . A second terminal of the variable resistor  115  is coupled to the VCC, and a negative terminal of the capacitor  116  is coupled to the ground. Pins  4  and  14  of the chip  113  are coupled to the VCC, and pin  7  of the chip  113  is coupled to the ground. Pin  6  of the chip  113  is coupled to a first terminal of a resistor  120  (10 k olms) and an output terminal of the inverter  138  (4049). 
     A second terminal of the resistor  120  is coupled to the VCC. Pin  5  of the chip  113  is coupled to a first terminal of a resistor  123  (10 k ohms), a first terminal of a resistor  132  (10 k ohms), and a first terminal of a resistor  128  (10 k ohms). Pin  3  of the chip  113  is coupled to a positive terminal of a capacitor  119  (0.1 μF), and a negative terminal of the capacitor  119  is coupled to the ground. Pins  1  and  2  of the chip  113  are coupled to a positive terminal of a capacitor  117  (33 μF) and a first terminal of a variable resistor  118 . A second terminal of the variable resistor  118  is coupled to the VCC, and a negative terminal of the capacitor  117  is coupled to the ground. A second terminal of the resistor  124  is coupled to a base terminal of the transistor  122 . 
     A cathode terminal of the diode  121  is coupled to a first terminal of a resistor  129  (10 k ohms), a first terminal of a resistor  124  (10 k ohms), and a cathode terminal of a diode  143  (1N4140). The second terminals of the resistors  124 ,  132 ,  128 , and  129  are coupled to the base terminals of the tristors  125 ,  131 ,  127 , and  130 , respectively. The collector terminals of the transistors  125  and  127  are coupled to the VCC. The emitter terminals of the transistors  131  and  130  are coupled to a first terminal of a resistor  133 . A second terminal of the resistor  133  is coupled to the ground. An emitter terminal of the transistor  125  and a collector terminal of the transistor  131  are coupled to a first terminal of the motor  126 . An emitter terminal of the transistor  127  and a collector terminal of the transistor  130  are coupled to a second terminal of the motor  126 . 
     An output terminal of the inverter  134  is coupled to a first terminal of a resistor  135  (10 k ohms). A second terminal of the resistor  135  is coupled to a collector terminal of the transistor  139  and a first terminal of a capacitor  136  (0.1 μF). A second terminal of the capacitor  136  is coupled to an input terminal of an inverter  138  and a first terminal of a resistor  137  (1M ohm). A second terminal of the resistor  137  is coupled to the ground A base terminal of the transistor  139  is coupled to a first terminal of a resistor  140  (10 k ohms), and an emitter terminal of the transistor  139  is coupled to the ground. A second terminal of the resistor  140  is coupled to a base terminal of the transistor  127  and a collector terminal of the transsor  141 . A base terminal of the transistor  141  is coupled to a first terminal of the resistor  142 , and an emitter terminal of the transistor  141  is coupled to the ground. A second terminal of the resistor  142  is coupled an anode terminal of the diode  143  and an output terminal of the inverter  144 . An input terminal of the inverter  144  is coupled to a first terminal of a resistor  146  (1M ohm) and a positive terminal of a capacitor  145  (2.2 μF). A negative terminal of the capacitor  145  is coupled to the ground, and a second terminal of the resistor  146  is coupled to the VCC. 
     FIG. 8 illustrates a detailed schematic of the motor controller circuit and the microphone preamplifier circuit which is implemented on the PC board  23  of FIG. 6. A contact microphone  200  is coupled to a preamplifier circuit which filters and amplifies certain frequencies such that an input signal can be distinguished between a telephone ring and other extraneous sounds. The contact microphone  200  is coupled to a jack plug  202 . The 2.5 mm jack plug  202  has a first terminal coupled to the ground. A second terminal of the jack plug  202  is coupled to a first terminal of a resistor  201  (2.2 k ohms) and a first terminal of a capacitor  203 . A second terminal of the resistor  201  is coupled to a first terminal of a resistor  204  (10 k ohms), a first terminal of a resistor  209  (180 k ohms), and 8.8 volts dc. A second terminal of the capacitor  203  is coupled to a base terminal of an npn transistor  207  (2N4401) and a first terminal of a resistor  204  (820 k ohms). 
     A second terminal of the resistor  204  is coupled to a second terminal of the resistor  205 , a first terminal of a capacitor  206 , and a collector terminal of the transistor  207 . A emitter terminal of the transistor  207  is coupled to a first terminal of a resistor  208  (510 k ohms). A second terminal of the resistor  208  is coupled to the ground. A second terminal of the capacitor  206  is coupled to a second terminal of the resistor  209 , a first terminal of a resistor  210  (22 k ohms), and a V+ terminal of an operational amplifier  211  (LM324). A second terminal of the resistor  210  is coupled to the ground. Pin  4  of the operational amplifier  211  is biased to 8.8 volts dc, and pin  11  is coupled to the ground. A V− terminal of the operational amplifier  211  is coupled to a first terminal of a resistor  212  (1M ohm). A second terminal of the resistor  212  is coupled an output terminal of the operational amplifier  211  and a first terminal of a resistor  213  (10 k ohms). 
     A second terminal of the resistor  213  is coupled to an anode terminal of a diode  214  (1N4148). A cathode terminal of the diode  214  is coupled to a positive terminal of a capacitor  215  (2.2 μF), a first terminal of a resistor  216  (220 k ohms), and a V+ terminal of an operational amplifier  217  (LM324). A V− terminal of the operational amplifier  217  is coupled to a first terminal of a resistor  219  and a first terminal of a resistor  281  (34 k ohms). A second terminal of the resistor  219  is coupled to the ground, and a second terminal of the resistor  218  is coupled to an output terminal of the operational amplifier  217 , a first terminal of a resistor  220  (1M ohm), and a cathode terminal of a diode  221  (1N4148). A second terminal of the cresistor  220  is coupled to an anode terminal of the diode  221 , a positive terminal of a capacitor  225  (2.2 μF), a first terminal of a resistor  222  (56 k ohms), and a V+ terminal of an operational amplifier  223  (LM324). Negative terminals of the capacitor  225  and the capacitor  215  are coupled to the ground. A second terminal of the resistor  222  is coupled to 8.8 volts dc. A V− terminal of the operational amplifier  223  is coupled to a first terminal of a resistor  224  (90 k ohms), and a second terminal of the resistor  224  is coupled to the ground. An output terminal of the operational amplifier  223  is coupled to a first terminal of a resistor  226  (1M ohm) and a first terminal of a resistor  227  (1M ohm). 
     A second terminal of the resistor  227  is coupled to an anode terminal of a diode  228  (1N4148). A second terminal of the diode  228  is coupled to a second terminal of the resistor  226 , a positive terminal of a capacitor  229  (1 μF), and a V+ terminal of an operational amplifier  231  (LM324). A negative terminal of the capacitor  229  is coupled to the ground. A V− terminal of the operational amplifier  231  is coupled to a first terminal of a resistor  293  (27 k ohms) and a first terminal of a resistor  230  (100 k ohms). A second terminal of the resistor  293  is coupled to 8.8 volts dc, and a second terminal of the resistor  230  is coupled to the ground. An output terminal of the operational amplifier  231  is coupled to a first terminal of a resistor  232  (1 k ohm). A second terminal of the resistor  232  is coupled to a ring detection signal module on a third terminal of a jumper switch  233 . A first terminal of the jumper switch  233  is coupled to an anode terminal of a diode  291 . A cathode terminal of the diode  291  is coupled to a 12 volt unregulated power source. A fourth terminal of the jumper switch  233  is coupled to the ground. 
     Further, as illustrated in FIG. 8, a third terminal of the jumper switch  233  is labeled hook on/off signal and is coupled to a first terminal of a resistor  235  (100 k ohms) and a first terminal of a resistor  234  (100 k ohms). A second terminal of the resistor  234  is coupled to the ground. A second terminal of the resistor  235  is coupled to a base terminal of an npn transistor  237  (2N4401). An emitter terminal of the transistor  237  is coupled to the ground. A collector terminal of the transistor  237  is coupled to a first terminal of a resistor  236  (100 k ohms), a input terminal of an inverter  238 , and an input terminal of an inverter  262 . A second terminal of the resistor  236  is coupled to 10 volts dc. An output terminal of the inverter  238  is coupled to an input terminal of an inverter  239 . An output terminal of the inverter  239  is coupled to a first terminal of a resistor  240  (10 k ohms). A second terminal of the resistor  240  is coupled to a collector terminal of an npn transistor  249  (2N4401) and a first terminal of a capacitor  241 . 
     An emitter terminal of the transistor  249  is coupled to the ground. A base terminal of the transistor  249  is coupled to a first terminal of a resistor  250 . A second terminal of the capacitor  241  is coupled to a first terminal of a resistor  242  and an input terminal of an inverter  245 . A second terminal of the resistor  242  is coupled to the ground. An output terminal of the inverter  245  is coupled to pin  8  of the a chip  247  (LM556CM) which is the trigger terminal. Pin  12  (threshold) and pin  13  of the chip  247  are coupled to a first terminal of a resistor  243  (412 k ohms), a first terminal of a capacitor  294  (1 μF), and a first terminal of a capacitor  244  (2.2 μF). A second terminal of the resistor  243  is coupled to 10 volts dc. Each second terminal of the capacitor  294  and the capacitor  244  is coupled to the ground. Pin  10  of the chip  247  is coupled to 10 volts dc, and pin  11  is coupled to a first terminal of the capacitor  246 . A second terminal of the capacitor  246  is coupled to the ground. Pin  9  (output) of the chip  247  is coupled to an anode terminal of a diode  248  (1N4148). An output terminal of the inverter  262  is coupled to a first terminal of the resistor  261 . A second terminal of the resistor  261  is coupled to a first terminal of the capacitor  257  and a collector terminal of an npn transistor  259  (2N4401). A base terminal of the transistor  259  is coupled to a first terminal of a resistor  258 , and an emitter terminal of the transistor  259  is coupled to the ground. A second terminal of the capacitor  257  is coupled to an input terminal of an inverter  253  and a first terminal of a resistor  256 . A second terminal of the resistor  256  is coupled to the ground. An output terminal of the inverter  253  is coupled to pin  6  of the chip  252  (LM556CM). Pins  1  and  2  of the chip  252  are coupled to a first terminal of a capacitor  955  (1 μF), a first terminal of a capacitor  255  (2.2 μF), and a first terminal of a resistor  254  (332 k ohms). Each second terminal of the capacitor  295  and the capacitor  255  is coupled to the ground. A second terminal of the resistor  254  is coupled to 10 volts dc. Pin  4  of the chip  252  is coupled to 10 volts dc. Pin  3  of the chip  252  is coupled to the first terminal of a capacitor  251 . A second terminal of the capacitor  251  is coupled to the ground. 
     A first terminal of a resistor  263  (1M ohm) is coupled to 10 volts dc. A second terminal of the resistor  263  is coupled to an input terminal of an inverter  264  and a first terminal of a capacitor  265  (2.2 μF). A second terminal ofthe capacitor  265  is coupled to the ground. An output terminal of the inverter  264  is coupled to an anode terminal of a diode  260  (1N4148) and a first terminal of a resistor  266  (47 k ohms). A second terminal of the resistor  266  is coupled to a base terminal of an npn transistor  267  (2N4401). An emitter terminal of the transistor  267  is coupled to the ground. A collector terminal of the transistor  267  is coupled to a base terminal of an npn transistor  270  (2N4401) and a first terminal of a resistor  271  (220 ohms). A second terminal of the resistor  271  is coupled to a second terminal of the resistor  250  and a first terminal of a resistor  281  (1 k ohm). A cathode terminal of the diode  260  is coupled to a second terminal of the resistor  258 , a cathode terminal of the diode  248 , a first terminal of a resistor  268  (220 ohms), and a first terminal of a resistor  277  (1 k ohm). 
     A second terminal of the resistor  268  is coupled to a base terminal of an npn transistor  269  (2N4401). A second terminal of the resistor  281  is coupled to a base terminal of an npn transistor  280  (2N4401). A second terminal of the resistor  277  is coupled to a base terminal of an npn transistor  278  (2N4401). A collector terminal of the transistors  269  and  270  are coupled to an emitter terminal of an npn transistor  287 . An emitter terminal of the transistor  269  is coupled to a first terminal of a resistor  272  (1 k ohm), pin  1  of a jumper  274 , and a collector terminal of the transistor  280 . An emitter terminal of the transistor  270  is coupled to a first terminal of a capacitor  273  (0.1 μF), pin  2  of the jumper  274 , and a collector terminal of the transistor  278 . A second terminal of the resistor  272  is coupled to a second terminal of the capacitor  273 . Emitter terminals of the transistors  278  and  280  are coupled to a first terminal of a resistor  279  (0 ohms). A second terminal of the resistor  279  is coupled to the ground. 
     A base terminal of the transistor  287  is coupled to a first terminal of a resistor  288  (1 k ohm). A second terminal of the resistor  288  is coupled to a first terminal of a potentiometer  289  (1 k ohm). A second terminal of the potentiometer  289  is coupled to a first terminal of a resistor  290  (560 ohms). A second terminal of the resistor  290  is coupled to the ground. A third terminal of the potentiometer  289  is coupled to the voltage VCC. A collector terminal of the transistor  287  is coupled to an unregulated 12 volt voltage supply. 
     Pin  3  of a chip  283  (LM317-LZ) is coupled to a first terminal of a capacitor  282  and 12 volts of unregulated dc. Pin  1  of the chip  283  is coupled to a first terminal of a resistor  284  (1.5 k ohms) and a first terminal of a resistor  285  (220 ohms. Pin  2  of the chip  283  is coupled to 8.8 volts dc, a positive terminal of a capacitor  286  (1 μF), and a second terminal of the resistor  285 . A second terminal of the capacitor  282 , a second terminal of the resistor  284 , and a negative terminal of the capacitor  286  are coupled to the ground. 
     FIG. 9 illustrates a block diagram for the present invention. The block  300  contains the initialization sequence which occurs upon powering up the present invention. The block  304  receives the incoming logic and provides logic detection. Upon detecting the logic, the block  304  sends the detected logic to the block  302 . The block  302  processes the logic and either activates the block  301  (Off Hook Timer) or the block  303  (On Hook Timer). Both of the blocks  301  and  303  provide the block  305  with the appropriate motor direction and the appropriate predetermined amount of time the motor is activated. In order to ensure that the telephone handset fully returns to the on-hook position, the block  303  activates the motor for a longer time duration than the block  301 . The block  306  receives the direction and time duration for the proper operation. 
     A commercial device embodying the present invention is being developed and is anticipated that it will be introduced during the first quarter of 1997 by Hello Direct, Inc. It is configured to cooperate with an improved version of the cordless headset of FIG.  1 . In particular, haedset  400 FIG. 10 receiver circuit will activate upon removal from the charging cradle. With the microphone boom  406  in the up position, all other circuits of the headset  400  remain inactive to conserve the battery. 
     Upon detection of an incoming call as a result of a ringing signal, the device of the present invention will communicate the ringing condition to the headset base unit  404  which in turn will provide an appropriate signal to the receiver circuit of the headset  400 . The headset  400  will provide an audible signal to the user via the ear piece  402 . If the user decides to answer the incoming call, the microphone boom  406  will be lowered. That action will activate the remaining circuits of the headset  400  and cause the headset  400  to generate a pick-up signal which is communicated to the headset base unit  404  and then to the device of the present invention which will raise the handset in response. 
     Upon termination of a call, the user will raise the microphone boom  406 . This action deactivates all circuits of the headset  400  except the receiver circuit and concurrently transmits a hang-up signal to the headset base unit  404 . The hang-up signal is communicated to the present invention to lower the telephone handset onto the cradle and take the telephone on hook, thereby. This remote notification and two-way communication allows a user to receive and terminate calls from a location remote from their telephone set. 
     Returning to FIG. 6, the clutch band  22  found inside the clutch housing  21 , transfers the energy created by the motor  27  to the handset arm  15  such that the handset arm can be raised and lowered. The clutch band  22  also prevents the motor  27 , as well as the parts coupled to the motor  27 , such as the handset arm  15 , the handset shaft  16 , and the drive shaft  18  from becoming over-stressed. Without the clutch band  22  to prevent excessive force, the additional time the motor is activated in the on-hook direction relative to the off-hook direction could cause damage to the motor  27  and to the parts coupled to the motor  27 . Additionally, the clutch band  22  also safeguards against possible damage to the motor  27  and its coupled parts while operating in the off-hook direction when there is an unexpected obstacle in the path of the handset arm  15 , the handset shaft  16 , or the drive shaft  18 . 
     Proper alignment of the handset to the lift-arm  19  when the handset is lifted is maintained by adjusting the amount of time during which the motor  27  lifts the handset in a minimum. Preferably, the height above the cradle to which the handset is lifted is thereby minimized to that which is just sufficient to reliably activate the hook switch of the telephone. Otherwise, as the handset is lifted higher than necessary, it is more likely to slip or shift relative to the handset arm  15 . To further prevent such slipping, the handset arm  15  is preferably covered with a anti-slip padding, such as rubber or foam rubber. 
     In addition, because the telephone set rests upon the platform  17  which is coupled to the handset arm  15  by the pedestal  12  and the handset shaft  16 , a unitary structure for the telephone set and handset pick-up device is provided. This unitary structure aids in maintaining proper alignment of the handset to the cradle by preventing the forces associated with lifting the handset from forcing the pick-up device out alignment with the handset and with the telephone cradle. As the handset is gently lowered over the hook switch, the motor  27  drives the handset arm  15  downward beyond a point at which the handset is expected to be lowered into the cradle to ensure that the telephone is reliably placed on-hook, while the clutch  22  limits the amount of force that can be applied to the telephone set. Because a unitary structure for the telephone set and handset pick-up device is provided by resting the telephone set on the platform  17 , proper alignment of the handset to the cradle is maintained by preventing the forces associated with the clutch  22  slipping after the lift-arm  19  contacts the telephone from forcing the pick-up device out alignment. Accordingly, the clutch  22  provides sufficient force to gently and reliably raise and lower the telephone handset without causing misalignment between the handset and the cradle of the telephone resting on the platform  17  and without causing damage to the handset, the hook switch or to the telephone set. 
     The motor control portion of the circuits, in FIGS. 6 and 7, control the pick up and hang up of the telephone handset via the motor  27  and the appropriate structure in the base unit. While taking into account the height adjustable pot  26  of FIG. 6, the motor control circuit adjusts the amount of time the motor  27  operates in the pick up direction to accommodate different pick up heights that are characteristic to various corded telephones. Further, to ensure that the handset is fully on the hook after the call is complete, the motor control circuit operates the motor  27  in the on-hook direction for a slightly longer duration tanm in the off-hook direction. Preferably, this longer time duration is 115% of the time during which the motor  27  is activated to lift the handset. 
     The microphone pre-amplification circuit found in FIG. 8 amplifies and filters out specific frequencies that are received from the contact microphone  200 . The pre-amplification circuit prevents extraneous noises from providing erroneous ring signals to the base unit of the present invention. Additionally, the pre-amplification circuit must also provide the correct notification of the ring signals from the corded telephone. Because the present invention is designed to operate with a variety of corded telephones from different manufacturers each with possibly different characteristic ring signals, the pre-amplification circuit must correctly sense a variety of ring signals. 
     While the preferred embodiment of the present invention has been illustrated and described as an integrated circuit using bipolar transistors, it will be apparent to a person of ordinary skill in the art that the circuit of the present invention may be implemented using another device technology, including but not limited to CMOS, MOS, discrete components and ECL. It will also be apparent to those skilled in the art that different logic circuit configurations could be substituted for the logic circuit described above to perform the functions of the preferred embodiment. 
     The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. Such reference herein to specific embodiments and details thereof is not intended to limit the scope of the claims appended hereto. For example, specific values are given to capacitors and resistors which are only to facilitate the understanding of the principles of construction and operation of the invention. It will be apparent to those skilled in the art that modifications may be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention.