Northern Telecom Limited

Beverley W Gumb

Alan C Busche

Gerd Kuhfus

Raymond C Freeman

Edward J Foster

Eric Foster

James N Schmidt

Guy J Chaput

Fredrick T Cogan

Algirdas J Dragunevicius

Edward M Sich

Laurence J Retallack

Ronald J Morrell

William D Greason

John S Mecher

Richard J Elgie

A telephone base with a display unit having a housing which is pivoted to the base. To locate the display unit in any desired angular position in simple manner, the housing has a convex outer surface formed on a constant radius centered on the pivotal axis and a plurality of parallel grooves are provided upon the surface and extending axially. The grooves are engageable by a free end of a leaf spring which is mounted directly to the housing.

Telephone base with a display unit

A pushbutton and cover combination for operating an electronic switching device, such as a telephone or keypad. The cover defines a number of button receiving apertures extending therethrough. Each button comprises a body having a first part which provides a contact surface and a second part which is slidably received through an individual one of the apertures, so that the contact surface of the button is accessible from a first side of the cover. Latches on the second part of the button body are cooperable with the cover so that the button is held captive in the cover, with the second part of the body being operable to move slidably within the aperture, for engaging a flexible barrier layer and operating the electronic switching device on an underlying circuit board. The subassembly of the cover with the captive buttons is removable intact from the circuit board and flexible barrier layer of the electronic switching device. After removal of the subassembly, the latches are accessible and the buttons are removable from the cover.

Pushbutton and carrying member combination for operating an electronic

A telephone base member and base support member combination in which there are two support members. The two support members may be assembled together and as an assembly may be mounted upon the base member. This arrangement provides a first angle of support for the base member upon a support surface. Alternatively, only one of the support members is mounted upon the base member. This arrangement provides for a different angle of support.

Telephone base members and support members

A telephone base structure having an underwall and another wall overlying the underwall. Spaced-apart cantilever beams in the underwall carry support feet at free ends of the beams. The beams are resiliently flexible upwards for the purpose of stabilizing the base structure upon a support surface with the overlying wall acting as a stop to limit the upward movement of the beams.

Telephone base structures for stabilizing upon support surfaces

Assembly of handsets is accomplished without the use of mechanical fastenings. Energy directors are provided at the peripheral edges of one of the two housings forming a handset, and the two housings are united by sonic welding. Severe damage can be caused to transducers mounted in the handset by sonic welding, but the use of energy directors directs the sonic energy around the transducers, avoiding damage. The transducers can be held in place by heatstaking positioning members. A rigid assembly which is readily amenable to automated assembly is provided.

Telephone handset having housings assembled without mechanical fasteners

A telephone handset for use in noisy locations has a noise cancelling electret transmitter which receives a normal acoustic input at the front end and a background noise acoustic input to the rear end. The input to the rear end is via a grill on the back side of the handset. A dielectric shield is positioned between the grill and the transmitter. A resistor is inserted in series with the transmitter to reduce the sensitivity and produce a lower than normal transmit level. Also, a filter is used to reduce the level of high frequency emphasis.

Telephone handset for use in noisy locations

A modular jack for a telephone, particularly for use in a handset, has a minimal height or profile by using a circuit board, on which the jack is mounted, as one of the walls defining the aperture into which a modular plug is inserted. The overall height of the jack is reduced by the thickness of the circuit board. The jack and board assembly has the smallest height dimension possible.

Low profile circuit board mounted telephone jack

A circuit pattern on a circuit board usually has a number of contact areas to which components are soldered. Some of the contact areas have holes extending through the board for insertion of leads of leaded components, the leads then being flow soldered to the contact areas. It often occurs that additional leaded components are to be mounted on the board after a first flow soldering step. However, holes through which the leads are to pass can be closed by solder. These holes are therefore masked mechanically, by a masking member which contacts the board at these holes, or by tape, or other such method. The present invention uses a conventional solder resist layer, usually applied prior to flow soldering, extending the solder resist layer over a part of the contact area to the periphery of the hole, the hole having an unplated bore or wall. The resist layer extends for at least part of the hole periphery. This prevents the solder being attached to the contact area at the masked periphery and the hole is not closed by a film of solder.

Masking of holes in circuit patterns on circuit boards prior to flow

A transmitter assembly for a telephone set uses a commercially available cartridge electric transmitter, by modifying the response curve. This is obtained by an adapter housing the transmitter with a first volume defined between the end of the transmitter and the end of the bore in which the transmitter fits. At the end of the bore there is an end wall with a hole therethrough, the hole covered with a layer of acoustic resistance material. A second volume is formed on the other side of the end wall, by a hollow formation on the wall of the transmitter housing of the handset. A slot is formed in the transmitter housing wall within the formation. The first volume provides damping, the hole and acoustic resistance material provides dB limitation at a particular frequency (1000 Hz) and the second volume and slot provide resonance at a second frequency (3000 Hz).

Transmitter assembly for a telephone handset

A dynamic telephone receiver which is capable of being used in association with hearing aids, has a flux coil positioned around the pole piece and magnet assembly. To minimize the strong magnetic leakage field radiated from the air gap, which can attract pins, paper clips and other ferrous metals a shunt can be provided at the face of the receiver. However, this also shunts or at least severely attenuates the AC field produced by the flux coil for inductive coupling to hearing aids. The shunt of this invention shunts only the leakage flux from the air gap with minimal effect on the AC field from the flux coil. The shunt is in the form of a cup, with a central aperture in the front face, surrounded by an annular ring which is connected to the outer wall of the cup by narrow arms. The inner circumference of the ring is formed down towards the magnet to form a lip which attracts stray flux from the air gap. The shunt also acts to hold the receiver assembly together.

Dynamic telephone receiver with magnetic shunt

An electret microphone has a metal shield around it in order to guard against electromagnetic interference. Acoustic waves reach the electret element through a passage in the shield. The electret response is undesirably affected by an electric field produced by body capacitance when the microphone is brought close to a user's mouth. To overcome this effect, the microphone has a conductive film, transparent to acoustic waves, positioned between the passage and the electret element, the film contacting a grounded part of the casing. The conductive film can form an integral part of a microphone moisture barrier.

Electret microphone shield

A telephone transmitter including an electret transducer is connected to an electrical circuit mounted in the transmitter housing. A resistor which can be of varying value is also connected to the circuit, the value of the resistor being adjusted to bring the operating characteristics within predetermined values. This is done by applying a sound signal of known frequency to the transducer and measuring the output characteristics of the transducer. This enables the suitable value of resistor to be connected into the circuit. By this means variations arising from varying atmospheric conditions at assembly, and other causes, can be allowed for. The metallized strip or film of the electret is preferably mounted with a very slight Vee shaped formation to avoid tight manufacturing tolerances which occur with a straight, or flat, strip.

Adjustment of operating characteristics of a telephone transmitter

A telephone transmitter sub-assembly has an electret clamped between a pair of printed circuit boards. The electret conducting surface and printed circuit patterns on the boards have an overlapping arrangement at a planar junction. The arrangement connects a capacitor, of which the electret forms part, into an amplifying circuit.

Electret microphone with simplified electrical connections by printed

A telephone set has a base member which is in the form of a flexible bag substantially filled with small pellets or similar material. The bag fits against the outside of the base of a substantially rigid housing with flaps on the bag extending up the outside of the housing and folding over and down the inside of the housing. Means are provided for attaching flaps to the housing. The assembled bag and housing fit over and enclose the telephone set base. The housing can have its sides divided into sections by slots to permit flexing of the sides as the housing is pushed onto the telephone set base.

Telephone set base member with bean bag attachment

An adaptor enables telephones using the later type of miniature plugs to be used with the conventional telephone outlet. The adaptor has a housing having pins in the base which plug into the conventional outlet. The cover carries a miniature jack on the inside, the jack in two parts, upper and lower. The lower part is molded integral with the cover and defines a plug-receiving cavity. An aperture in the cover is aligned with this cavity. The upper part of the jack has contacts extending therethrough, the contacts bent down and round to extend rearwards in the cavity for contact by terminals in the jack. The contacts are connected to the pins in the base of the housing.

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London, Canada

Beverley W Gumb