GB2195511A

GB2195511A - A telephone handset assembly

Info

Publication number: GB2195511A
Application number: GB08622746A
Authority: GB
Inventors: Colin Warsop
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1986-09-22
Filing date: 1986-09-22
Publication date: 1988-04-07
Anticipated expiration: 2006-09-22
Also published as: GB2195511B; GB8622746D0

Abstract

A telephone handset assembly for converting a purely acoustic telephone transducer 5 to one suitable for use with an inductive device. The assembly has an adaptor 1 into which transducer 5 (for example a "3T" transducer) is inserted. The transducer 5 is connected to the handset via a coil of conductive wire 9 held by the adaptor 1. The adaptor 1 is also arranged to adapt the 3T transducer to fit a hendset arranged to receive a 4T transducer. <IMAGE>

Description

SPECIFICATION A telephone handset assembly The present invention relates to a telephone handset assembly and more particularly to such assemblies designed for use with a deaf aid device.

The normal acoustic output from a telephone handset transducer is usually insufficient to adequately interact with an external device. A typical solution to this problem is to provide a modulated magnetic field which is dependent on the speech currents incident upon for example the receiver transducer. The modulated magnetic field being more readily "picked up" by an induction coil provided in the deaf-aid device.

The modulated magnetic field is produced in a conductive coil wound around the periphery of the receiver transducer and connected in series with that receiver transducer. Consequently signal currents received by the receiver transducer are also received by the coil which generates a corresponding magnetic field dependent on the value of the signal current according to Lenz's law.

A typical telephone receiver adaptor assembly for deaf-aid compatible telephones thus has a receiver transducer with a coil of wire wound around it for deaf-aid interaction compared to the normal receiver transducer. A problem of the previous deaf-aid compatible assemblies is thus that a specific receiver transducer had to be produced adding both to cost of production and adding to the problems of fabrication. Additionally, it is usual for the coil to be of 150 turns which may add housing accomodation problems in modern slim-style phones.

It is an objective of the present invention to provide a telephone receiver assembly which uses a conventional receiver transducer while maintaining the facility of enhanced deaf-aid interaction.

According to the present invention there is provided a telephone handset assembly comprising an electro-acoustic transducer and an adaptor member arranged to accomodate the electroacoustic transducer and the adaptor having magnetic induction means serially coupled to the electro-acoustic transducer for providing from an applied signal a magnetic field response corresponding to the acoustic response of the electro-acoustic transducer thereby to enable the telephone handset to interact with an external induction device without modification to the electro-acoustic transducer.

According to a further feature of the invention there is provided an adaptor member for enabling an eiectro-acoustic transducer of a telephone handset to interact with an induction device external to the handset, the adaptor member being arranged for accomodation of the electro-acoustic transducer and comprising magnetic induction means for serial coupling to the electro-acoustic transducer for providing from an applied signal a magnetic field response corresponding to the acoustic field response of the electro-acoustic transducer.

Preferably, the magnetic induction means should be a conductive coil and the magnetic induction means maybe positionable before, after or with a portion either side of the receiver transducer.

The adaptor member may be made of a plastics material and the conductive coil from copper wire.

The adaptor with the magnetic induction means may be oriented to be normal to the external induction device improving magnetic interaction.

An embodiment of the present invention will now be described by way of example only withreference to the accompanying drawings in which: Figure 1 is a plan view of a telephone receiver assembly according to the present invention; and, Figure 2 is a part cross-sectional view of the telephone receiver assembly on the line ll-ll of figure shown with a typical receiver transducer.

Consider figures 1 and 2, the telephone receiver assembly has an adaptor or former member 1 with a flanged bore 3 to accomodate a receiver transducer 5. In use the receiver transducer 5 is secured inan abutting position with flange 7. A coil of conductive wire 9 is formed in the adaptor member 1 in a groove 11.

The coil 9 is connected in series with both the telephone handset wires and the receiver transducer 5. Consequently, any current signals passing through the circuit thus constructed stimulates an acoustic response in the receiver transducer 5 and a magnetic field in the coil 9.

Typically with the coil 9 attached between terminals 15 and 17 and with terminals 19 and 21 short circuited, the terminals may be connected as follows: Terminal Connection 15 Handset wire A 17 Receiver transducer wire A 19 Receiver transducer wire B 21 Handset wire B Thus ensuring an electrical series connection, although it may be appreciated that the coil could be placed before or after the receiver transducer, or with a portion before and a portion after the transducer to improve balance.

In the present invention a standard acoustic type transducer such as that known in the United Kingdom as the "3T" transducer is used which has the adaptor 1 with coil 9 to provide the magnetic field thus making construction or conversion of a deaf-aid compatible telephone much cheaper.

In particular a "3T" transducer may be used with the adaptor in a handset aperture normally provided for use with a "4T" type transducer thereby avoiding the need to provide either a modified handset or a modified transducer to provide facilities to assist hearing impaired users.

Although, the above embodiment involves a receiver transducer it will be appreciated that a coil in a telephone handset microphone transducer could be used to "pick up" signal currents and could be used with an inductance coil in external apparatus for inductive coupling in a data transmission system.

The adaptor member 1 can be made of a plastics material and the conductive coil made from copper wire. The conductive coil may be preformed and the adaptor moulded around it.

Claims

1. A telephone handset assembly comprising an electro-acoustic transducer and an adaptor member arranged to accomodate the electro-acoustic transducer and the adaptor having magnetic induction means serially coupled to the electro-acoustic transducer for providing from an applied signal a magnetic field response corresponding to the acoustic response of the electroacoustic transducer thereby to enable the telephone handset to interact with an external induction device without modification to the electro-acoustic transducer.

2. A telephone handset assembly as claimed in claim 1 wherein the magnetic induction means is connected prior to the transducer in electrical series.

3. A telephone handsetassembly as claimed in claim 1 wherein the magnetic induction means is connected after the transducer in electrical series.

4. A telephone handset assembly as claimed in claim 1 wherein the magnetic induction means is arranged such that a portion thereof is connected before the transducer and a portion thereof is connected after the transducer in electrical series.

5. A telephone handset assembly as claimed in any preceding claim wherein in use of the handset the magnetic induction means is arranged such that it is oriented substantially parallel to the external induction device.

6. A telephone handset assembly as claimed in any preceding claim wherein in use of the handset the magnetic induction means is oriented to be normal to the external induction device.

7. A telephone handset assembly as claimed in any preceding claim wherein the magnetic induction means is a conductive coil.

8. A telephone handset assembly as claimed in claim 7 wherein the coil is formed from copper wire.

9. A telephone handset assembly as claimed in claim 7 or claim 8 wherein the coil is wound around the periphery of the adaptor member.

10. A telephone handset assembly as claimed in any preceding claim wherein the adaptor member is made of a plastics material.

11. A telephone handset assembly, as claimed in any preceding claim wherein the magnetic induction means is enclosed within the adaptor member.

12. A telephone handset assembly as claimed in any one of claims of the preceding claims comprising a further acoustic transducer and a further adaptor member having magnetic induction means serially coupled to the further acoustic transducer.

13. A telephone handset assembly as claimed in any preceding claim wherein the transducer is a receiver transducer of the assembly.

14. A telephone handset assembly as claimed in any one of claims 1 to 12 wherein the transducer is a transmitter transducer of the assembly.

15. An adaptor member for enabling an electro-acoustic transducer of a telephone handset to interact with an induction device external to the handset, the adaptor member being arranged for accomodation of the electro-acoustic transducer and comprising magnetic induction means for serial coupling to the electro-acoustic transducer for providing from an applied signal a magnetic field response corresponding to the acoustic field response of the electro-acoustic transducer.

16. A telephone handset assembly substantially as hereinbefore described with respect to the accompanying drawings.