GB2256112A - Answering system - Google Patents

Abstract

This invention relates to an answering system (10) which is initiated when a caller rings the door bell (12). The caller may leave a message in response to instructions which are transmitted to him from a telephone answering machine (48), or the like. The message is transmitted back to the answering machine and recorded. <IMAGE>

Description

ANSWERING SYSTEM This invention relates to an answering system, and, in the most important example, to an answering system for answering the door when an occupier is unavailable.

It is known to provide an intercom device in order that a visitor can communicate with the occupier of a premisis prior to opening of a street door. However, if the occupier is unavailable to answer the intercom or is out, there is no way he can know who the visitor is or indeed that anyone has visited.

According to the present invention there is provided an answering system comprising: an answering system comprising initiating means, actuable by a visitor, for initiating the system and causing a signal to be produced, which signal activates a transceiving means; wherein the transceiving means transmits a message to the visitor and receives and stores a message from the visitor.

Reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a block diagram of an answering system according to one embodiment of the invention; and Figure 2 is a more detailed block diagram of the part of the Figure 1 system.

Referring to the Figures 1 and 2, an answering system is shown generally at 10. When a push button 12 on a door, for example, is activated an electric bell (not shown per se) is actuated by closure of switch 14. The push button also initiates the answering system by generating a signal which is equivalent to a telephone signal so that a conventional telephone answering machine 48 acts as though a telephone ringing signal has been received. The initiation of the answering system occurs by closure of switch 16, which connects a power supply 18 to the system. The power supply, is, for example, a 15V DC supply. A trigger 20 now emits a trigger signal to a master timer 22. This allows a pulse generator 24 to pass pulses through a gate 26. In general up to six pulses are produced each time the master timer opens the gate.Each pulse is typically of two seconds duration and spaced from the next pulse by one second. The pulses switch on an oscillator power supply 28 in order that the output from a 25Hz oscillator 30 is on for two seconds and off for one second, for up to six cycles. The output voltage is typically lOV peak to peak.

This voltage is applied to a primary coil 32 of a first transformer 34. The secondary coil 36 of the transformer forms part of a current loop 38. The transformation (or turns) ratio of the transformer 34 is 1:10. Hence, the voltage across the secondary coil is about lOOV peak to peak.

The current loop 38 further includes a second secondary coil 40 of a second transformer 42, a resistor 44, and a DC battery 46 or a power supply (not shown) and is connected to a telephone answering machine 48. The first transformer 34 introduces the pulses into the current loop. Receipt of two, three, four, five or six of these pulses causes the answering machine to be activated in a similar manner to when an incoming telephone signal is received.

Activation of the answering machine causes the current loop to be closed and a current of about 20mA can then flow around the loop driven by the DC battery 46. The voltage of the battery is typically between 12 and 15V. The current is then detected by a detector 50.

The detecter then produces a signal to feedback to gate 26, inhibiting further pulses from passing. This also causes the gain of a loudspeaker ampliier 52 to go high and remain so under the influence of a logic circuit 66 and a gain control circuit 68.

A voice signal is generated by the telephone answering machine and is superimposed on the current flowing in the loop. This causes a voltage to be developed across resistor 44. A typical value for the resistor is 1005. The voltage produced is amplified by the loud speaker amplifier 52 when it is in a state of high gain and is then transmitted to a loudspeaker 54. The loudspeaker is located outside the door in the general proximity of push button 12. A message and/or any instructions are thus transmitted to the caller. The caller may then leave a return message by speaking into a microphone 56 which is located near the loudspeaker.

The signal produced is amplified by a microphone amplifier 58 and introduced into the current loop by transformer 42. The transformation (or turns) ratio of the transformer 42 is 1:1. The voltage across coil 40 causes a current signal to flow and a message to be recorded on the answering machine. It is preferred that when the caller leaves a message a push button 60 be depressed throughout the duration of the message. The push button causes switch 62 to close. This then causes three functions:a) a Light Emitting Diode (LED) 64 is illuminated on the outside of the door so long as switch 62 remains closed.This indicates to the caller that their message is being recorded; b) under the influence of the logic circuit 66 and the gain control circuit 68, the gain of loudspeaker amplifier 52, which up till then was high, then remains low even if switch 62 is opened; and c) again under the influence of the logic circuit 66 and a gain control circuit 70, the gain of microphone emplifier 58 is increased and is held high so long as switch 62 remains closed.

The latter two functions reduce the unwanted accoustic feedback between the microphone and loudspeaker. The logic circuit is configured such that the microphone amplifier 58 has high gain only when switch 62 is closed and loop current is detected by detector 50.

When switch 62 is open, the microphone amplifier reverts back to low gain and the LED goes off, but both these can be re-established so long as there remains a signal coming from detector 50. The answering machine then detects a lack of input and switches itself off. This causes the current loop to be open loop, which in turn causes the feedback signal produced by detector 50 to cease. Thus gate 26 is now re-opened for any subsequent activation.

Referring to Figure 2 certain functional blocks of the Figure 1 system are illustrated in more detail. When the push button 12 is depressed and switches 14 and 16 are closed, a signal passes through a signal conditioner 72 to a 15 second monostable 74. The output of monostable 74 becomes one of the inputs of an AND gate 76. A second input on the AND gate is supplied by a loop 78 which includes a 1 second monostable 80 and a 2 second monostable 82. In combination this acts like pulse generator 24. The third input is supplied by a comparator 88 which detects current flow in the current loop, and is also connected via a NOT gate 84 to push button 60. The factors controlling the state of the third input will be described later. Assuming all the inputs to AND gate 76 are high the output will also be high in the form of up to six pulses as previously described. The pulses are supplied via gate 26 to oscillator power supply 28 and thence to oscillator 86 which provides the 10V peak to peak voltage supplied to coil 32.

The current detector 50 includes the comparator 88 which is connected to a supply 92 on one input and to a low pass filter resistor capacitor couple 90 on another input. The low pass cut-off frequency of the filter couple is typically about 15Hz. The filter couple is located across resistor 44.

Thus when a current flows in the current loop there is a filtered voltage across the resistor of the filter couple, this is detected by the comparator which generates a signal such that a low is produced at the third input of AND gate 76. If there is no current in the loop the comparator causes the third input of the AND gate to be high.

The voltage generated across resistor 44 and applied to the input of loudspeaker amplifier has its DC component removed using a capacitor 94.

A bypasscapacitor 96 is located across the secondary coil 36 to allow the various voice signal currents to pass round the loop unimpeded by the inductance of secondary coil 36. It also smooths the waveform of the 25Hz 100V peak to peak oscillation appearing across the secondary coil 36.

Once the caller has received a message and instructions from the answering machine, the caller may be instructed to depress button 60 and speak into the microphone. When the button is depressed the following occurs:a) the signal supplied by NOT gate 84 from comparator 88 is passed to LED 64 which is thereby turned on; b) gain control 68 and gain control 70 are controlled by a logic circuit shown generally at 98.

This circuit 98 includes two signal conditioners 100 and 102 which supply the inputs of a bistable 104. The output from the bistable is fed directly to gain control 68 to lower the gain of loudspeaker amplifier 52 when the button 60 is depressed. The output from the bistable is also fed through a NOT gate 106 to one input of an AND gate 108.

The other input of AND gate 108 is supplied directly when switch 62 is closed.

If both inputs of the AND gate are high, as is the case when switch 62 is closed, the output of the AND is also high and gain control 70 increases the gain of the microphone amplifier.

It should be noted that all voice signals are superimposed on the current flowing in the current loop in order that the voice signals are transferred to and from the answering machine.

It should also be noted that the answering machine may be supplemented or replaced with other receiving apparatus 110. For example, a conventional telephone may be connected in parallel to enable conversation between the caller and occupant. Other receiving apparatus includes a mobile phone, extension phones etc.

It should further be noted that the circuit shown is only one possible means of carrying out the invention. It will understand that some or all of the components could be replaced by others which have the same function.

Claims (9)

1. An answering system comprising; initiating means actuable by a visitor, for initiating the system and causing a signal to be produced, which signal activates a transceiving means; wherein the transceiving means transmits a message to the visitor and receives and stores a message from the visitor.

2. An answering system according to Claim 1, wherein the transceiving means includes a telephone answering machine.

3. An answering system according to Claim 1 or 2, wherein the initiating means includes a door bell or the like.

4. An answering system according to any preceding claim, wherein the transceiving means includes a microphone and a loudspeaker in the vicinity where the visitor actuates the initiating means.

5. An answering system according to any preceding claims; further including first amplifier means for amplifying the message sent to the visitor and second amplifier means for amplifying the message sent by the visitor.

6. An answering system according to any preceding claim, further including inhibiting means for inhibiting the message to the visitor when the message from the visitor is sent.

7. An answering system according to claim 6, wherein the inhibiting means suppresses the gain of the first amplifier means and increases the gain of the second amplifier means.

8. An answering system according to Claim 6 or 7, wherein the inhibiting means includes display means for indicating that the inhibiting means is in operation.

9. An answering system, substantially as described with reference to the accompanying drawings.