JPS5846758A - Telephone device - Google Patents

Abstract

PURPOSE:To avoid the leakage of a dial tone out of a speaker in an on-hook dial mode, by feeding a call signal or the input of the receiving loudspeaking call by means of a transformer. CONSTITUTION:The call signal fed through a channel 20 is supplied to a telephone amplifier 22 via a tansformer 28 and then delivered through a speaker 3. While the input of the receiving loudspeaking call of a trunk line is supplied to the amplifier 22 via a transformer 29 and then delivered through the speaker 3. In this case, a switch 24 is closed in order to avoid the howling between a transmitter T and the speaker 3. For a receiver R, a switch 23-1 is broken. At the same time, the primary side impedance of the transformer 29 is set equivalent to the impedance of the receiver R. Thus the load fluctuation is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone device, such as a button telephone device, equipped with a telephone amplifier.

In a conventional key telephone device, as shown in Fig. 1, an amplifier 1 for inputting calling signals such as a central office line incoming signal, an extension calling signal by tone or voice, and a calling signal from a doorbell, and an amplifier 2 for inputting loudspeakers are installed in the telephone. and one configured to have a switch 11 and a switch 11 according to the input as shown in FIG.
! There was one that was configured to switch between the two signals and input them to the amplifier l.

In addition, 4 is a switch, 5 is a telephone circuit, 6 is a handset, and 7
8 is a control circuit that controls the switches 4, 11, and 12 using a key, and 8 is a power supply circuit. In either case, the receiving loudspeaker input is from station IIJ! 10 itself, in the case of push-button dialing, when on-hook dialing, the dial signal sent out from the central office line 16-ttc is directly input to the amplifier 1.2, so a huge level of sound is output to the speaker. It may appear more than 3. Furthermore, in the case of a rotary dial, noise may be generated from the dial's shunt contacts, so countermeasures are required.

As described above, the conventional methods have drawbacks both functionally and economically. In order to solve these drawbacks, the present invention
The present invention provides a telephone device equipped with a telephone amplifier which inputs a call signal, etc., and amplification input using a transformer.

The present invention will be explained in detail below.

FIG. 3 shows an embodiment of the present invention, in which 20 is an extension communication line and a central office line, 21 is a communication circuit, 22 is a telephone amplifier constituted by an AGC circuit 3θ and an amplifier 31, and 23-1.2
3-2.23-3.24.25-1.25-2.26-
1.26-2, 32-1, 32-2 are switches,
27-1 and 27-2 are hook switches, and 28 and 29 are input quadrants. In this embodiment, the present invention is applied to a button telephone device in which the number of core wires in a cable is reduced.

The call signal input from the communication path 20 is sent to the [switch 26-
1.26-2 → transformer section] route to telephone amplifier 2
2 and output from speaker 3.

Next, regarding the reception amplification input of the office line, the audio of the office line is [talk path 20 → switch 25-1, 25-2 → switch 32
-1.32-2 → Call circuit 21 → Switch 23-2.2
The signal is inputted to the telephone amplifier 22 via the route 3-body→transformer 29], and is outputted from the speaker 3. At this time, the transmitter T
The switch 24 is set to "make" in order to prevent noise between the speaker 3 and the speaker 3. Further, for the receiver R, the switch 23-1 is set to break, and the primary impedance of the transformer 29 is made equal to the impedance of the receiver R, thereby suppressing load fluctuations.

Since the call signal input is sent from the main device of this device,
Although the signal can be supplied to the telephone amplifier 22 at a sufficient level, the level fluctuates depending on the connection state of the office line regarding the reception amplification input of the central office line.In order to prevent the influence of these fluctuations, the telephone amplifier 22 is provided with an AGC circuit 3θ. This reduces fluctuations in output level due to fluctuations in input level.

In addition, since the reception amplification input for the office line is taken from the end of the handset, there is no possibility that the dial signal of the push button dial or the noise of the front F contact of the rotary dial will reach a huge level and be output from the speaker 3 during on-hook dialing. %A
.

4@dTransformer 28 in Figure 3. This is an embodiment in which four are combined into one using an intermediate tap on the primary side. In this embodiment, only the case with one office line has been described, but the difference in the number of office lines does not exceed the scope of this claim.

As explained above, according to the present invention, the function can be realized by simply installing one amplifier in the telephone, and since the input of the loudspeaker is taken from the end of the handset, there is no problem during on-hook dialing. There are advantages.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional example having two amplifiers in a telephone, Fig. 2 is a block diagram of a conventional example using an amplifier configured to switch inputs, and Fig. 3 is a circuit showing an embodiment of the present invention. 4 are circuit diagrams showing a partial modification of the embodiment shown in FIG. 3. Patent Applicant: Iwasaki Tsushinki Co., Ltd. Nippon Telegraph and Telephone Public Corporation Agent: Tsuneo Shiramizu Oita 10th

Claims (3)

[Claims] (1) A telephone device equipped with a telephone amplifier in which a ringing signal input and a loudspeaker input are input through at least one transformer. (2) The transformer is matched-coupled to the communication path in order to receive the input of the calling signal, etc., and is matched-coupled to the handset terminal of the communication circuit network in order to receive the input of the reception amplification. A telephone device according to claim 1. (3) The telephone device according to claim 2, wherein the transformer is a single transformer having an intermediate tap on the primary side.