GB1602575A - Acoustic coupler - Google Patents

Description

(54) AN ACOUSTIC COUPLER (71) We, THE BISHOP OF THE ROMAN CATHOLIC CHURCH IN HONG KONG, a corporation sole incorporated under Chapter 1003 of the laws of Hong Kong, of Bishop's House, No. 2 Caine Road, Hong Kong, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to an acoustic coupler for use with a telephone handset.

It is an object of the invention to provide an acoustic coupler for use as a reception and transmission interface between an ordinary telephone receiver and a further communication system.

Accordingly, the present invention provides an acoustic coupler having a hollow rest for supporting a telephone handset provided with an earpiece spaced apart from a mouthpiece, the rest having a reception acoustic chamber and a transmission acoustic chamber which are adapted to be closed respectively by the earpiece and the mouthpiece of a handset supported on the rest, the reception and transmission chambers being acoustically insulated from one another by an internal partition of the rest and by a packing of sound insulating material within the rest, a coupling microphone being arranged to receive acoustic signals transmitted into the reception chamber by the telephone earpiece and to deliver electrical audio signals for transmission to a further communication system, a coupling loudspeaker being arranged to transmit acoustic signals into the transmission chamber to the telephone mouthpiece in response to electrical audio signals delivered to the coupling loudspeaker by the further communication system and a frustoconical coupling seal of resilient material being provided in the reception acoustic chamber with its smaller diameter end attached to the coupling microphone to form a tight soundproof coupling chamber between the coupling microphone and the telephone earpiece.

Preferably, the coupling microphone is a condenser microphone.

Advantageously, the output of the coupling microphone is connected to an equalizer for improving the signal to noise ratio of the electrical audio signals delivered by the microphone. The equalizer may, with advantage, be housed within the said rest of the acoustic coupler.

In an embodiment of the invention, the rest of the acoustic coupler is mounted in a base portion of a rectangular housing having a hinged lid portion with side walls which rest on the top edge of the base portion. Preferably, the depths of the hinged lid increases from the hinged edge thereof to the opposite edge.

An acoustic coupler according to the invention finds particular application in teaching apparatus and, according to another aspect, the invention provides teaching apparatus for enabling a teacher to communicate via a plurality of telephone extensions simultaneously with a number of remote students, comprising a teacher's control panel connected to a plurality of acoustic couplers according to claim 1 and each for coupling to the handset of a respective telephone extension, the teacher's control panel comprising a reception mixlrg circuit for mixing the electrical audio signals from the coupling microphones of the acoustic couplers associated with the teacher's panel and delivering the mixed received signals to, a teacher's loudspeaker, a transmission mixing circuit for mixing the mixed received signals with a signal frown a teacher's microphone and delivering the mixed transmission and received signals to the coupling loudspeakers of the acoustic couplers associated with the teacher's panel, means for controlling the mixing levels of the individual coupling microphones, and means for controlling the mixing levels of the signals mixed by the transmission mixing circuit.

The reception mixing circuit may also deliver the mixed received signals to a reception tape recorder for recording the mixed received signals.

The transmission mixing circuit may mix the mixed received signals with the transmission signal from the teacher's microphone and also, with a recorded signal from a transmission tape recorder.

In order that the invention may be readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a vertical section through an acoustic coupler embodying the invention; FIGURE 2 is a diagram of the layout of teachmg apparatus employing acoustic couplers embodying the invention; FIGURE 3 shows the interconnections made to a teacher's control panel; and FIGURE 4 is a front elevation of the teacher's control panel.

Referring firstly to Figure 1, an acoustic coupler comprises a hollow rest 1 mounted in a base portion 2 of a rectangular housing or box 3 having a hinged lid portion 4. The lid portion 4 has side walls, such as 5, which rest on the top edge of the base portion 2, the depth of the lid portion 4 increasing from the hinged edge to the free edge 6 thereof.

The rest 1 is adapted to support on the upper surface thereof a telephone handset (nor shown) provided with an earpiece spaced apart from a mouthpiece. The upper surface of the rest 1 comprises oppositely inclined portions 7 and 9 which are interconnected by a central portion 8. Within the rest 1 are formed a cylindrical reception acoustic chamber 10 and a cylindrical transmission aroustic chamber 11 which are acoustically insulated from one another by a packing of foam rubber 12 within the rest 1 which alsc, has an internal partition 13 between the chambers 10 and 11. The chamber 10 opens onto the portion 9 of the upper surface of the rest 1 and the chamber 11 opens onto the portion 7.

A condenser coupling microphone 14 is mounted in the internal wall of the coupling chamber 10 and has leads 15 extending, via an equalizer 16 for improving the signal to noise ratio of the microphone output, to, a multi-pin socket 17 provided in a back wall 18 of the box 3. A frusto-conical rubber seal 19 fixed in the chamber 10 extends from the microphone 14 to the surface portion 9 of the rest, the smaller diameter end of the seal being located around the microphone 14.

A coupling loudspeaker 20 is mounted in the internal wall of the coupling chamber 11 and has leads 21 extending to socket 17. Further acoustic insulation 22 is provided in the chambers 10, 11 around the periphery thereof.

In use of the described acoustic coupler, the telephone handset is placed on the upper surface of the rest 1 and the relative angles of the surface portions 7, 8 and 9 are such, that with a middle part of the hand-set resting on the surface portion 8, the earpiece and the mouthpiece of the handset overlie and close off the chambers 10 and 11 respectively. The seal 19 provides tight coupling between the earpiece and microphone 14, while a looser coupling exists between the mouthpiece and loudspeaker 20. The microphone 14 receives acoustic signals transmitted into the chamber 10 by the telephone earpiece and delivers corresponding electrical audio, signals for utilization in a further communication system, such as the teaching apparatus to be described hereinafter.The loudspeaker 20 transmits acoustic signals into the transmission chamber and thus to the telephone mouthpiece in response to electrical audio signals delivered to the loudspeaker from the further communication system.

Figure 2 shows the basic form of teaching apparatus embodying the invention, in which a plurality of teachers can each communicate simultaneously with a number of students via a plurality of telephone receivers each having its handset coupled to a teacher's control panel via an acoustic coupler as described with reference to Figure 1. Figure 2 shows how incoming calls from students on lines 30 are distributed via a PMBX 31 associated with an operator's work bench 32 to a number of lecture rooms 33 each provided with thirty telephone extensions 34 only one of which is shown in the schematic drawing of Figure 2.

The operator's workbench 32 provides a visual indication of whether each extension is engaged or free and has means enabling the operator to terminate a call by disconnecting an incoming call from an extension. The workbench enables the operator to initiate outside calls and then transfer the called party to an extension. When the caller hangs up the PMBX automatically releases the extension and frees the incoming external line 30. No offhook tone is required for the extensions and no dialling and ringing facility is required for the extension.

Figure 3 shows the equipment in a lecture room 33. This equipment includes a teacher's control panel 35 to which the handsets of the thirty telephone extensions are connected by respective couplers embodying the invention.

Figure 3 shows the coupling microphones 14 connected to a reception mixer 36 in the teacher's control panel, where the electrical signals from the microphones 14 are combined and then amplified by amplifier 37 for reproduction by the teacher's loudspeaker 38. The output of the amplifier 37 is also fed to a reception cassette tape recorder 42 for recording the mixed received signals, if desired.

A teacher's microphone 39 is connected via a transmission mixer 40 and amplifier 41 to the coupling loudspeakers 20 of the acoustic couplers. The mixer 40 serves to mix the teacher's microphone signal with the output of amplifier 37 and with the signal from a transmission cassette tape recorder 42', if desired.

As shown in Figure 4, a front face of the teacher's control panel 35 presents control sliders 43, for controlling the rmring levels of tne individual coupling microphones 14 and control sliders 44 for controlling the mixing levels of the three components of the signal fed to the coupling loudspeakers 20. A visual indicator 45, such as a telltale lamp, is also pro vided for indicating the status of each extension. The cassette tape recorders 42, 42' are also mounted on the front face of the control panel for easy access. Jacks 46 and 47 are provided for the teacher's microphone and loudspeaker respectively.

In use of the described teaching apparatus, the operator, upon receiving a call, ascertains from the caller which lecture room the caller requires. The operator then determines whether any of the extensions in the required lecture room is free by inspecting the visual indicators on the workbench. If there is a free extension for the requested lecture, the operator connects the caller to the extension. When the caller hangs up, the corresponding extension is set free automatically and the associated indicator at the operator's workbench indicates a free extension. At the end of the lecture, the operator disconnects all callers connected to the lecture room.

The equipment in the lecture room can be used by the teacher as follows. When a visual indicator 45 is on at the teacher's panel, it means a student is on the line. The teacher can choose a student with whom he wishes to communicate using the appropriate control slider 43. If the teacher wishes to, log a question from a student, he can switch on the reception tape recorder 42. If the teacher wishes to give a lecture he may pre-record the lecture on the transmission tape recorder 42' or give it live using the microphone. In the event that the teacher wishes to disconnect a student, he can instruct the operator to, carry out the disconnection, the communication between teacher and operator being via an inter-com system separate from the telephone network and teaching apparatus.

WHAT WE CLAIM IS:- 1. An acoustic coupler having a hollow rest for supporting a telephone handset provided with an earpiece spaced apart from a mouthpiece, the rest having a reception acoustic chamber and a transmission acoustic chamber which are adapted to be closed respectively by the earpiece and the mouthpiece of a handset supported on the rest, the reception and transmission chambers being acoustically insulated from one another by an internal partition of the rest and by a packing of sound insulating material within the rest, a coupling microphone being ararnged to, receive acoustic singals transmitted into the reception chamber by the telephone earpiece and to deliver electrical audio signals for transmission to a further communication system, a coupling loudspeaker being arranged to transmit acoustic signals into the transmission chamber to the telephone mouthpiece in response to electrical audio signals delivered to the coupling loudspeaker by the further communication system, and a frusto conical coupling seal of resilient material being pmvided in the reception acoustic chamber with its smaller diameter and attached to, the coupling microphone to form a tight sound-proof coupling chamber between the coupling microphone and the telephone earpiece.

2. A coupler according to claim 1, wherein the coupling microphone is a condenser microphone.

3. A coupler according to claim 1 or 2, wherein the output of the coupling microphone is connected to an equalizer for improving the signal to noise ratio of the electrical audio signals delivered by the microphone.

4. A coupler according to claim 3, wherein the equalizer is housed within the rest of the acoustic coupler.

5. A coupler according to any preceding claim, wherein the coupling seal is made of rubber.

6. A coupler according to any preceding claim, wherein the said rest of the acoustic coupler is mounted in a base portion of a rectangular housing having a hinged lid portion with side walls which rest on the top edge of the base portion.

7. A coupler according to claim 6, wherein the depth of the hinged lid increases from the hinged edge thereof to the opposite edge.

8. Teaching apparatus for enabling a teacher to communicate via a plurality of telephone extensions simultaneously with a number of remote students, comprising a teacher's control panel connected to a plurality of acoustic couplers according to claim 1 and each for coupling to the handset of a respective telephone extension, the teacher's control panel comprising a reception mixing circuit for mixing the electrical audio signals from the coupling microphones of the acoustic couplers associated with the teacher's panel and delivering the mixed received signals to a teacher's loudspeaker, a transmission mixing circuit for mixing the mixed received signals with a signal from a teacher's microphone and delivering the mixed transmission and received signals to the coupling loudspeakers of the acoustic couplers associated with the teacher's panel, means for controlling the mixing levels of the individual coupling microphones, and means for con trilling the rnixing levels of the signals mixed by the transmission mixing circuit.

9. Teaching apparatus according to claim 8, wherein the reception mixing circuit also delivers the mixed received signals to a reception tape recorder for recording the mixed received signals.

10. Teaching apparatus according to claim 8 or 9, wherein the transmission mixing circuit mixes the mixed received signals with the trans

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. vided for indicating the status of each extension. The cassette tape recorders 42, 42' are also mounted on the front face of the control panel for easy access. Jacks 46 and 47 are provided for the teacher's microphone and loudspeaker respectively. In use of the described teaching apparatus, the operator, upon receiving a call, ascertains from the caller which lecture room the caller requires. The operator then determines whether any of the extensions in the required lecture room is free by inspecting the visual indicators on the workbench. If there is a free extension for the requested lecture, the operator connects the caller to the extension. When the caller hangs up, the corresponding extension is set free automatically and the associated indicator at the operator's workbench indicates a free extension. At the end of the lecture, the operator disconnects all callers connected to the lecture room. The equipment in the lecture room can be used by the teacher as follows. When a visual indicator 45 is on at the teacher's panel, it means a student is on the line. The teacher can choose a student with whom he wishes to communicate using the appropriate control slider 43. If the teacher wishes to, log a question from a student, he can switch on the reception tape recorder 42. If the teacher wishes to give a lecture he may pre-record the lecture on the transmission tape recorder 42' or give it live using the microphone. In the event that the teacher wishes to disconnect a student, he can instruct the operator to, carry out the disconnection, the communication between teacher and operator being via an inter-com system separate from the telephone network and teaching apparatus. WHAT WE CLAIM IS:-

1. An acoustic coupler having a hollow rest for supporting a telephone handset provided with an earpiece spaced apart from a mouthpiece, the rest having a reception acoustic chamber and a transmission acoustic chamber which are adapted to be closed respectively by the earpiece and the mouthpiece of a handset supported on the rest, the reception and transmission chambers being acoustically insulated from one another by an internal partition of the rest and by a packing of sound insulating material within the rest, a coupling microphone being ararnged to, receive acoustic singals transmitted into the reception chamber by the telephone earpiece and to deliver electrical audio signals for transmission to a further communication system, a coupling loudspeaker being arranged to transmit acoustic signals into the transmission chamber to the telephone mouthpiece in response to electrical audio signals delivered to the coupling loudspeaker by the further communication system, and a frusto conical coupling seal of resilient material being pmvided in the reception acoustic chamber with its smaller diameter and attached to, the coupling microphone to form a tight sound-proof coupling chamber between the coupling microphone and the telephone earpiece.

2. A coupler according to claim 1, wherein the coupling microphone is a condenser microphone.

3. A coupler according to claim 1 or 2, wherein the output of the coupling microphone is connected to an equalizer for improving the signal to noise ratio of the electrical audio signals delivered by the microphone.

4. A coupler according to claim 3, wherein the equalizer is housed within the rest of the acoustic coupler.

5. A coupler according to any preceding claim, wherein the coupling seal is made of rubber.

6. A coupler according to any preceding claim, wherein the said rest of the acoustic coupler is mounted in a base portion of a rectangular housing having a hinged lid portion with side walls which rest on the top edge of the base portion.

7. A coupler according to claim 6, wherein the depth of the hinged lid increases from the hinged edge thereof to the opposite edge.

8. Teaching apparatus for enabling a teacher to communicate via a plurality of telephone extensions simultaneously with a number of remote students, comprising a teacher's control panel connected to a plurality of acoustic couplers according to claim 1 and each for coupling to the handset of a respective telephone extension, the teacher's control panel comprising a reception mixing circuit for mixing the electrical audio signals from the coupling microphones of the acoustic couplers associated with the teacher's panel and delivering the mixed received signals to a teacher's loudspeaker, a transmission mixing circuit for mixing the mixed received signals with a signal from a teacher's microphone and delivering the mixed transmission and received signals to the coupling loudspeakers of the acoustic couplers associated with the teacher's panel, means for controlling the mixing levels of the individual coupling microphones, and means for con trilling the rnixing levels of the signals mixed by the transmission mixing circuit.

9. Teaching apparatus according to claim 8, wherein the reception mixing circuit also delivers the mixed received signals to a reception tape recorder for recording the mixed received signals.

10. Teaching apparatus according to claim 8 or 9, wherein the transmission mixing circuit mixes the mixed received signals with the trans

mission signals from the teacher's microphone and also with a recorded signal from a transmission tape recorder.

11. An acoustic coupler substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

12. Teaching apparatus substantially as hereinbefore described with reference to the accompanying drawings.