JPH0443750A - Hand-free telephone set - Google Patents

Abstract

PURPOSE:To prevent voice deterioration from being caused without provision of a changeover switch by providing a connection means stopping a function of a hand-free circuit when the connection between a hand-free microphone and a control terminal is disconnected between the hand-free microphone and the control terminal. CONSTITUTION:A switch circuit 4a attached to a jack (connection means) 4 with a hand-free microphone attached/detached thereto/therefrom is connected to a control terminal 2, the other terminal of the switch circuit 4a is connected to ground, and when a plug is inserted to the jack 4, the switch circuit 4a is connected thereto. A hand-free circuit 1 is active in interlocking with the connection of the hand-free microphone. When the hand-free microphone is not connected, since the telephone set acts like an ordinary telephone set entirely, no sound quality deterioration is incurred and no provision of a changeover switch is required.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hands-free telephone that allows a line connection to be made without removing the handset from the main body.

BACKGROUND OF THE INVENTION Normally, when a telephone is connected to an outside line, the handset is removed from the main unit, the telephone goes on-hook, dialing is performed, and once the line is connected, the handset is used to make a call. There is.

However, this does not free up your hands when you want to take notes while talking, and it is inconvenient for multiple people to talk on the same phone at the same time, so it is better to place the handset on the main unit. There are hands-free telephones that allow you to connect to a line and make calls using a built-in microphone and speaker.

When installing a hands-free function in this type of telephone, various measures are taken, such as adding a circuit such as a howling canceller, to prevent the sound emitted from the speaker from being input to the microphone and causing howling. ing.

In addition, in order to meet the diverse needs of recent years, the hands-free microphone can be removed from the main body and used as a regular telephone, or the manufacturer may have added a hands-free microphone to a model with the same design. Telephones with hands-free functionality and regular telephones without a hands-free microphone are also sold together with slight specification changes.

Problems to be Solved by the Invention However, in the conventional configuration as described above, the hands-free microphone is only removed from the main body (the hands-free microphone circuit is separated from the connection part), so the sound quality is poor. There was a problem in that it caused deterioration. Further, this problem can be solved by providing a changeover switch within the main body, but this not only increases the number of parts and costs, but also requires securing installation space.

The present invention solves the above-mentioned conventional problems, and aims to provide a hands-free telephone that does not require a changeover switch and does not cause audio deterioration.

Means for Solving the Problems In order to solve the above-mentioned problems of the prior art, the present invention provides a hands-free microphone, which allows hands-free operation when a high level voltage is applied, and which enables hands-free operation when a high level voltage is applied. a hands-free circuit having a control terminal that stops the hands-free operation when the hands-free operation is stopped; and a hands-free circuit that is provided between the hands-free microphone and the control terminal, and that stops the function of the hands-free circuit when the connection between the two is broken. and a connecting means.

Operation: Therefore, according to the present invention, the level control of the control terminal provided in the hands-free circuit is performed depending on whether or not the hands-free microphone is connected. That is, the hands-free circuit is turned on in conjunction with the connection of the hands-free microphone. Therefore, when the hands-free microphone is not connected, the phone functions completely as a normal telephone, so there is no deterioration in sound quality. Further, there is no need to provide a changeover switch.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described. FIG. 1 is a circuit diagram of the main parts of a hands-free telephone according to a first embodiment of the present invention.

The hands-free circuit 1 includes a voice output function during on-hook dialing, a call function after the line is connected, etc.
It is stored inside the phone body. This hands-free circuit 1 is connected to a main circuit consisting of a rectifier circuit, a ringer circuit, a pulse oscillation circuit, etc. (not shown). The hands-free circuit 1 includes a control terminal 2, and a pull-up resistor 3 is connected between the control terminal 2 and the electric fiVa so that the control terminal 2 indicates an H" level when it is open. A switch circuit 411 attached to the jack 4 (connection means) for attaching and detaching the free microphone is connected.The other end of the switch circuit 4a is grounded, and when the plug is inserted into the jack 4, Switch circuit 4a is short-circuited (connected)
is configured to be

The operation of the above configuration will be described below.

When a hands-free microphone (not shown) is inserted into the switch circuit 4a, the switch circuit 4a is in an on state, and the control terminal 2 is grounded via the switch 4a. Note that the audio signal output from the hands-free microphone is input to the communication circuit via a circuit not shown. Therefore, the hands-free circuit 1 operates and functions as a hands-free telephone, and it is possible to make a call without removing the handset from the main body. On the other hand, when the hands-free microphone is removed from the jack 4, the switch circuit 4a is turned off and the control terminal 2 is set to H''.
level. Upon receiving this level signal, the hands-free circuit 1 becomes inactive and stops its function. Since the hands-free circuit 1 does not operate, the deterioration in sound quality is eliminated.

As described above, according to this embodiment, when the hands-free microphone is inserted into the jack 4, it functions as a hands-free telephone, and when the hands-free microphone is removed from the jack 4, it functions as a normal telephone. Furthermore, since there is no need to provide an independent switch for this switching, the circuit can be simplified and costs will not increase.

Next, a second embodiment of the present invention will be described. FIG. 2 is a circuit diagram of the main parts of a hands-free telephone according to a second embodiment of the present invention.

In this embodiment, the hands-free microphone is connected to the hands-free circuit 1 using the jack 2 in the first embodiment, whereas the present embodiment connects the hands-free microphone to the hands-free circuit 1 using a connector (connection means). It has characteristics.

That is, a 4-pin connector 5 connected to the control terminal 2 is provided on the telephone side, and a connector 6 that fits into the telephone side connector 5 is provided on the hands-free microphone 7 side.

The output of a hands-free microphone 7 is connected to pins 1 and 2 of the telephone side connector 5 and the microphone side connector 6. Further, pins 3 and 4 of the microphone side connector 6 are connected, and the control terminal 2 is connected to the pin 3 of the telephone side connector 5, and the pin 4 is grounded.

The operation of the above configuration will be described below.

When the microphone-side connector 6 is connected to the telephone-side connector 5, the control terminal 2 is grounded and becomes the "L" level as in the first embodiment, the hands-free circuit 1 becomes operational, and the telephone function is disabled. It becomes a hands-free phone. - On the other hand, when the microphone side connector 6 is unplugged from the telephone side connector 5, pins 3 and 4 of the telephone side connector 5 become open, the control terminal 2 becomes "H level", and the hands-free circuit 1 becomes inactive. As a result, there is no possibility of sound quality deterioration as in the above embodiment.

Effects of the Invention As described above, according to the present invention, a hands-free microphone enables hands-free operation when a high level voltage is applied, and stops the hands-free operation when a low level voltage is applied. A hands-free circuit having a control terminal; and a connecting means provided between the hands-free microphone and the control terminal to stop the function of the hands-free circuit when the connection between the two is broken. By removing the hands-free microphone, it can be operated as a normal telephone without deteriorating sound quality, and there is no need to provide a changeover switch, making it possible to improve operability.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the main parts of a hands-free telephone according to the first embodiment of the invention, and FIG. 2 is a circuit diagram of the main parts of the hands-free telephone according to the second embodiment of the invention. 1... Hands-free circuit, 2... Control terminal, 3... Pull-up resistor, 4... Shack, 4a.
...Switch circuit, 5...Telephone side connector, 6...
・Microphone side connector, 7...Microphone for hands-free use.

Claims (1)

[Claims] A hands-free microphone, a hands-free circuit having a control terminal that enables hands-free operation when a high-level voltage is applied and stops the hands-free operation when a low-level voltage is applied, and the above-mentioned hands-free microphone. and a connection means provided between the control terminal and the control terminal, and stopping the function of the handsfree circuit when the connection between the two is broken.