CA1171987A - Telephone tactile alert system - Google Patents

Abstract

A TELEPHONE TACTILE ALERT SYSTEM
Abstract of the Disclosure A telephone user who cannot hear the telephone ringing is alerted, other than audibly, to the fact that the telephone must be answered. A radio transmitter at the telephone is driven by ringing voltage supplied to the instrument. The transmitter emits a radio signal which is picked up by a receiver carried by the telephone user.
Upon detection of the received signal, a tactile transducer is actuated and alerts the telephone user to the fact that the telephone must be answered.

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Description

13~7~9~37 This invention relates to a system for alerting a telephone user who cannot hear the telephone ringing, that the telephone should be answered.
Quite often, and for a variety of reasons, a ringing telephone will not be heard. The telephone user may be deaf. The bell volume may be deliberately turned down, perhaps in consideration of someone else sleeping on the premises. There may be the noise of a vacuum cleaner, radio, television or gramaphone record which drowns the sound of the ringing telephone. Lastly, the telephone user may be in the garden or garaqe or otherwise remote from the telephone set and so too far away to hear the ringing.
In such circumstances, a system for alterting the telephone user would be convenient.
According to the invention, there is provided a system for altertinq a telephone user when the telephone is being energized by rinqing voltage, the devtce comprising a telephone unit including a transmitter having an output which is controlled by ringing voltage on the telephone line, and a user unit including a receiver for receiving a signal from the transmitter, and a transducer under the control of the receiver for convertinq the received signal into a signal which is non-audibly sensible by the telephone user.
Preferably, the transducer is actuated to produce a physical vibration. The transducer can be mounted within a housing worn by the telephone user whereby to give a tactile response. The housing can, for example, be wrist worn. The user unit preferably includes a detector to detect a predetermined frequency of signal received by the receiver, the detector operably coupled to a low-power ~' ~.~

117~L~387 hattery-driven motor circuit. The transmitter is preferably mains driven, ringinq voltage from the telephone line being applied to the transmitter through an optical isolator whereby to prevent mains voltaqe and system noise from appearing on the telephone line.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:-Figure 1 is a block schematic diagram of an alertingsystem accordinq to the invention;
Figure 2 is a detailed circuit representation of a transmitter unit forming part of the system of Figure 1;
Figure 3 is a detailed circuit representation of a receiver unit forming part of the system of Figure 1; and Figure 4 shows a wrist mounted housing for the Figure 3 circuit.
Referrinq in detail to the block schematic diagram of Figure 1, there is shown a telephone tactile alert system. Ringing voltage from a telephone line 10 is applied both to a telephone set 12, and, through an optical isolator 14, to a pulse generator 16 which controls the output of a radio transmitter 18. While ringing voltage is present on the telephone line, the transmitter 18 emits a radio frequency signal which is picked up by a receiver 20. A detector 22 ~ monitors the received signal and, in response to a selected frequency ; component above a pre-set threshold level, actuates a transducer 24 which converts the received signal to a physical vibration. The vibration elicits a tactile response in a user wearing the receiver unit.

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1 ~ 7~L9~7 Referring now to Figure 2, the transmitter unit has a plun 26, which mates with one socket of a standard double socket wall mounted ~junction unit which is connected to the telephone line. The other socket is engaqed hy a plug electrically connected to the telephone set.
A 0.7 V output generated at a voltage tap 34 is directed to the optical isolator 14 when ringing voltage is present. The voltage tap includes a capacitor 3fi to prevent oPeration in response to nc and low voltaqe signals. A zener diode 40 conducts when ringing n voltaqe (8nv RMS), is present; a further diode 42 is incorporated for protection.
The optical isolator is a standard unit incorporating a linht emitting diode and a PIN photodiode. The output from the optical isolator is taken to a timer 44 (IC7555), which produces DC pulses with a 4 second-2 second mark-space duty cycle, pulse initiation correspondin~ to the start of ringing voltage pulses. DC power generated in network 28 is derived from mains AC.
The output from the timer 44 is directed to the base of a transistor n1 forming the first stage of a multi-stage transmitter 2n amplifier 48. The amplifier output enables a local oscillator circuit 51 which generates a carrier siqnal at a crystal controlled frequency of 53.1 MHz. The keyed carrier signal is directed to a short wire antenna 32 through a filter circuit 52.
Referring in detail to Figure 3, the receiver includes a crystal controlled local oscillator 54 at a frequency of 53.55 MHz. At a mixing circuit 56 the locally qenerated frequency is mixed with the incominq carrier frequency to generate an intermediate frequency of 1~L71987 ~sn KHz. The intermediate frequency signal is amplified at a multi-staqe amplifier 58, the output from which is rectified at transistor Q5. The nc output is taken to a threshold detection network includinq a low-power consuming VMOS switch 60. The switch, when actuated, directs current to a micromotor 62. One example of a suitahle motor which operates from a nominal supply of 1~ V and draws ahout 3n mA current can be obtained from ESCAP Inc. under the specification No. 712 L81 10S. An output shaft of the micromotor 62 is fitted with an eccentric weight (not shown) which causes the motor body to vibrate when the motor is energized. The network 64 functions essentially as a voltage regulator. A 6 V battery supply 66 supplies power to the receiver and detector.
Referring to Figure 4, the motor and the 1~ V battery are taped toqether and friction fitted into one compartment 72 of a moulded plastic bracelet 71. A tactile sensation is induced in the wearer's wrist by vibration of the motor body against a compartment wall. The 6 V battery together with the receiver and detector circuits are housed within a second compartment 76 of the bracelet. The bracelet has a web portion 78 offering rudimentary flexibility, the web portion extending hetween the compartments 72 and 76. Covers 80 adapted to close the compartments can be press fitted against the moulded bracelet, the covers and the moulding having cooperating ribs and recesses (not shown). Attached to lugs 82 formed at each of the compartments 72 and 76 are Velcro (Registered Trademark) strips 84 by means of which the bracelet incorporatinq the receiver unit can be secured around the user's wrist.
As previously indicated, in operation the ringing voltage actuates both the telephone set bell and the radio transmitter to emit ~ 71987 radio frequency hursts corresponding approximately in length to the lenqth of rinqinq voltaqe bursts. If a switch S1 shown in Figures 3 and 4 is placed in the "Orl" position, then the receiver unit receives the radio si~nal and produces corresponding vibration of the micromotor aqainst the wall of the bracelet. This produces a tactile response in the user who is thereby alerted that the telephone must be answered.
Upon pickinq up the telephone handset, rinqing voltage ceases as does vibration of the micromotor 62.
Althouqh the invention has been described in terms of a radio signal transmitted from a transmitter unit located adjacent to the telephone set, the transmitter output being modulated by ringing voltage, other tvpes of transmitter and receiver could be used. Thus the transmitter and receiver could alternatively be incorporated in an electroma~netic induction loop. As a further alternative, the transmitter and receiver could operate on the basis of infrared transmission.

Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A system for non-audibly alerting a telephone user when the telephone is being energized by ringing voltage, the system comprising (i) a telephone unit for coupling to the telephone lines, the telephone unit including a sensing means for sensing successive ringing voltage bursts and a transmitter adapted to emit a signal burst in response to each successive ringing voltage burst, and (ii) a user unit including a receiver for receiving the signal bursts from the transmitter and a transducer under the control of the receiver for converting the received signal into a non-audibly sensible signal.

2. A system as claimed in claim 1, in which the transmitter is a radio transmitter and the receiver is a radio receiver.

3. A system as claimed in claim 1, in which the sensing means and the transmitter are coupled through an optical isolator.

4. A system as claimed in claim 3, further including a mains power transformer for applying DC power to the transmitter.

5. A system as claimed in claim 1, in which the transmitter includes a timing network controlling the transmitter whereby to emit radio frequency bursts corresponding in length to ringing voltage bursts.