JPS63127693A - Telephone system - Google Patents

Abstract

PURPOSE:To attain external line and extension call through one and same telephone line by providing a common telephone line connected to a telephone line, plural telephone sets and a level switch means so as to bring a sent signal level to a conventional level at the external line call and to a level below the prescribed level at the extension call. CONSTITUTION:In connecting an extension to an external line directly, a signal sent level sent from the extension to the external line in case of the extension call is brought into a level below the specified level. Thus, each telephone set is provided with a voice signal transmission/reception means, an external line talking means communicating a voice signal in the range of a 1st level and an extension talking means communicating the voice signal in the range of a 2nd level being lower than the range of the 1st level. Moreover, each telephone line and voice signal transmission/reception means is provided a couple of switch means connecting the extension and external line communication means selectively and the extension/external line switch control means. Thus, the voice signal transmission/reception means is connected respectively to one and same telephone line at the external line call and the extension call.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone system that uses the same telephone line to make external calls and internal calls.

BACKGROUND OF THE INVENTION Conventionally, there are two types of telephone systems capable of making external calls and internal calls: types that use exchanges and types that do not use exchanges. Switched type telephone systems include, for example, a private branch exchange (PBX), a small private branch exchange (small PBX), or a key system unit KSU switch (Key System unit) in a key telephone system.
tem IJ+it) etc. are used.

As an example, FIG. 9 shows a multi-line telephone system (2
As shown in the diagram, a switchboard is placed at the boundary between the outside line and the internal line.
A number of telephones are commonly connected to both extensions 1 and 2. The exchange operates to electrically separate the extension line from the outside line during an extension call.

As a type of telephone system that does not use a switchboard, there is a telephone system in which a communication path dedicated to extensions is provided outside the telephone line for making extension calls. A typical example of this extension-only communication channel is a power line, and extension calls are made using an intercom that uses this power line.

In both of the above-mentioned conventional switched telephone systems and non-switched telephone systems, only one communication channel is provided in terms of signal level.
Because this single communication channel is shared by both external and internal calls, in exchange-based systems, it is necessary to install a switchboard at the boundary between internal and external lines, and to electrically separate internal lines from external lines when making internal calls. was there. The use of this switch includes installation work and wiring work for the switch, which makes the entire telephone system expensive.In addition, in this system, when internal calls and external calls are made at the same time using the same telephone line, I couldn't.

On the other hand, in systems that do not use exchanges, there is a problem in that it is necessary to provide a dedicated communication path for extension lines in addition to normal telephone lines. In addition, when using existing indoor power lines as this dedicated communication channel, noise sources such as electromagnetic cookers, personal computers, and televisions, which have been increasing in recent years, may cause problems.
There was a problem that good call sound quality could not be obtained.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a telephone system with a simple and inexpensive structure that allows external calls and internal calls to be made on the same telephone line without using a conventional switchboard or installing additional communication lines. The goal is to provide the following.

Another object of the invention is to provide a telephone system as described above which can be made multi-line.

In the telephone system of the present invention, when an extension line is directly connected to an outside line, the level of the signal sent from the extension line to the outside line during an extension call is set to be below a specified level. The focus is on the fact that extension calls can be realized by this. This transmission level is stipulated in the technical standards stipulated in the Public Telecommunications Act in Japan, and in Chapter 68 of the Federal Communications Commission (FCC) Regulations in foreign countries, such as the United States.

Therefore, in order to achieve the above-mentioned object, the present invention provides a common telephone line connected to a telephone line, a plurality of telephones connected to the common telephone line, and a plurality of telephones provided in each telephone, when making an internal call. and level switching means for switching the level of a signal sent from the telephone to the common telephone line depending on when an outside line call is being made.

As a result, the output signal level is set to a normal level during an outside line call, and is set to a lower predetermined level or less during an internal call, thereby making it possible to make an internal call and an outside call using a common telephone line.

The basic configuration of the telephone system of the present invention will be explained below with reference to FIG. 1 which shows the concept of the telephone system of the present invention. Note that this figure shows only one of the plurality of telephones connected to the telephone line. The remaining telephones have the same or similar configurations.As shown in the figure, in the telephone system of the present invention, the telephones are connected to a telephone line or a telephone line directly connected to an outside line, and each telephone audio signal transmitting/receiving means for transmitting and receiving signals; outside line communication path means capable of communicating the audio signals in a first level range; and extension channel means capable of communicating over a range of levels.

The telephone further includes a pair of switching means for selectively connecting an extension line communication path means and an outside line communication line means to each of the telephone line and the voice signal transmission/reception means, and an extension line for supplying a switching control signal to the pair of switching means. /external line communication path switching control means, which connects the audio signal transmitting/receiving means to the telephone line via the external line communication path means during an external line call, and connects the voice signal transmitting/receiving means to the telephone line via the external line communication path means during an internal line call. and connect to the telephone line.

Further, the extension communication path means can have a plurality of extension communication channels different from the external communication channel in order to enable two or more extension calls at the same time. Additionally, the telephone has switching control means connected to the telephone line for controlling internal and external telephone calls. This exchange control means has an exchange control communication channel different from the outside line communication channel, in order to be used for communication of exchange control signals below the predetermined level between a plurality of telephones via telephone lines. Accordingly, when a plurality of extension communication channels are provided, the exchange control means activates the extension communication channel specifying means to specify a channel to be used among the plurality of extension communication channels when making an extension call. generate a signal to

The above-mentioned extension/external call path switching control means receives, as input information for switching control, a signal from the ringer signal detection means, a signal from the extension/external call designation means, and a signal from the on/off hook detection means. , and a signal indicating the callable state of the called side of the extension coming from the exchange control means.

The above exchange control means receives, as input information for exchange control, a signal from a ringer signal detection means, a signal from an on/off hook detection means, an extension number from an extension number generation means at the time of an extension call, and others. receives an exchange control signal from the telephone.

Furthermore, the telephone system of the present invention has two telephone lines.
More than one line can be used to create a multi-line telephone system. In that case, two telephone lines can be connected to each of the telephone lines, and a plurality of telephones can all be connected to the two telephone lines.

Kenji K1 will now explain in detail a multi-line telephone system, which is one embodiment of the present invention, with reference to the drawings.

[Overall Configuration] FIG. 2 is an overall configuration diagram of this multi-line telephone system 10, and in this illustrated example, it is a multi-line system with two outside lines. Indoor extension lines 16.18 are directly connected to these two outside lines 12.14, respectively. For example, one master telephone unit 20 and seven slave telephone units 22 are connected to both of these extensions 16, 18 by phone jacks 24, respectively. Therefore, a total of eight telephone units are connected directly to outside lines without going through a conventional exchange.

[Outside the phone unit! ! ! ] FIG. 3 shows the appearance of the main body 30 of the master telephone unit 20 with the handset removed. Note that the other slave telephone units 22 also have the same appearance. This main body 30 includes a handset receiver 32) a hook switch 34, a telephone key 36, an outside line label 38, an outside line selection button 40, an extension call key 42) an extension number table 44.
, extension reception prohibition key 46. It is equipped with a hold key 48, a dial pulse output/DTMF (tone) output selection key 50, and in addition to this, a redial key 52) a Bose key 5
4, a flash key 56, a monitor key 58, and a dialing indicator 60.

[Telephone unit circuit] Next, the fourth section regarding the circuit of the master telephone unit 20 will be explained.
This will be explained with reference to the figures. In addition, slave telephone unit 2
The circuit of No. 2 is almost the same as the circuit of master telephone unit 20, except that there is no ringer detection circuit.

The circuit of this master telephone unit 20 includes an outside line switching relay 70 for each telephone line connected to extension 16 and extension 18.
A ringer detection circuit 74,76 is connected to each telephone line to detect ringer signals from the outside line 12 and the outside line 14. Bridge circuit 72 is further connected to speech network 82 via a mechanically and electrically actuatable hook switch 78 and pulse dialer 80. This speech network 82 is connected to the handset 31 via an extension/external line switching relay 84 . The output of a tone dialer 86 is connected to this speech network 82. The above-mentioned outside line 3M channel means generally include speech network 82) pulse dialer 80, hook switch 78
, a bridge circuit 72.

The handset 31 also connects the input of the channel FM modulation circuit 88 and the channel FM via the extension/external line switching relay 84.
It is connected to the output of the demodulation circuit 90. These FM modulation circuit 88 and demodulation circuit 90 operate at 280-400KHz.
It has four switchable carrier frequencies within the band.
Therefore, in one example having four communication channels CHO-CH3, the carrier frequency of each channel is CHO
280 KHz is selected for CHI, 320 KHz for CH2, 360 KHz for CH2, and 400 KHz for CH3. This constitutes the aforementioned multiple extension communication channels. The output of modulation circuit 88 and the input of demodulation circuit 90 are connected to each telephone line via transformer 92 and extension switching relay 94. Capacitors 98 and 100 connected between the extension switching relay and each telephone line are for cutting signals having a frequency lower than the carrier frequency used. The aforementioned extension communication path means generally includes a channel modulation circuit 88, a channel demodulation circuit 90, and a transformer 9.
2. Also, internal line/external line switching relay 84
, the outside line switching relay 70, and the extension switching relay 94 constitute the pair of switching means described above.

Furthermore, the transformer 92 includes a command FM modulation circuit 10.
2 and the input of the command FMfIi adjustment circuit 104 are connected. These modulation circuit 102 and demodulation circuit 104 operate at one carrier frequency (for example, 430±2 KHz) different from the four carrier frequencies described above. This constitutes the above-mentioned exchange control communication channel, and the input of the command modulation circuit 102 is connected to the microcomputer 11.
This command modulation circuit converts the received command into an audio signal, then FM modulates it during the period when the carrier wave is on, and sends it out.

On the other hand, the output of the command demodulation circuit 104 is
06 to give commands to the microcomputer 110. These command modulation circuits 102) command demodulation circuit 104, waveform shaping circuit 106
, transformer 92 forms part of the exchange control means described above.

The microcomputer 110 is a 4-bit microcomputer, and in this embodiment, it is a NECμPD7510.
I am using 6G. This microcomputer 110
As input information, the key output from the key 62 (this schematically shows the various keys shown in FIG. 3), the ringer detection signal from the ringer detection circuits 74 and 76, and the command return JH7J path 104 are input. It receives commands coming through the waveform shaping circuit 106. The key 62 constitutes the above-mentioned extension/external call designation means, extension number generation means, and on/off hook detection means.

The microcomputer 110 sends, as control signals, an internal line/external line switching signal to the relay 84, an external line switching signal to the relay 70, an internal line switching signal for switching the relay 94, and a hook on/off signal to the hook switch 78. Output. The microcomputer also outputs a CHO-CH3 selection signal for the channel modulation circuit 88 and demodulation circuit 0, and various commands for switching control to the command modulation circuit 102. In addition, the microcomputer 110 outputs signals to the light emitting diodes LED for various displays, and outputs dialer control signals to the pulse dialer 80 and tone dialer 86 for dialer transmission. This microcomputer constitutes the remaining portions of the above-mentioned exchange control means, an extension/external communication path switching control means, and an extension communication channel designation means.

[Sending Level] Next, the channel modulation circuit 88 and the command modulation circuit 1
02 Explaining the transmission level 1 According to the technical standards based on the provisions of Japan's Public Telecommunications Law, when the transmission level within the specified frequency band up to 4KHz is P dBm, the frequency above this specified frequency band The unnecessary transmission level in the band is specified for P dBm.

The above frequency band I! At 1280-432 KHz, the unnecessary transmission level is specified as P-60 dB or less.

Similarly, in the United States, for example, there is a regulation in Chapter 68 of the Federal Communications Commission Regulations, which states that this unnecessary transmission level is defined as ``If the leakage voltage from a tip (T) and ring (R) telephone set is the line voltage, , “The effective value (r m s ) of the line voltage component within the frequency range of 270 KHz-6 MHz is 2
The voltage shall not exceed -15 dBV when averaged over μs.

Therefore, each modulation circuit 88 and 102 is adjusted so that its output level range is below the unnecessary transmission level.

[Command] Next, commands will be explained with reference to FIG. Control information used for exchanges 1161 between telephone units 20.22 is communicated between them in the form of commands. This command includes a first type command consisting only of an operation code as shown in FIG. 5(a), and a second type command consisting of an operation code and a first and second operand as shown in FIG. There is a type command.

An example of a first type command is a ringer command. This ringer command is executed by the master telephone unit 20 when a ringer signal of a call from an outside line is detected.
to all slave telephone units 22 to notify these slave telephone units of the presence of a call from an outside line.

Next, examples of the second type command include an off-hook command, an extension call command, an extension callee response command, a hold command, and a transfer command.

The off-hook command is generated when going off-hook in response to a call from an outside line or from an extension, or when notifying other telephone units that a line has been connected to an outside line or an extension. The operation code has a code indicating off-hook. The first operand is the outside line number (number 1 or 2 indicating one of the two outside lines selected by the outside line selection button 40 in FIG. 3).
) or the number of the extension line (1 or 2), and the second operand is the number (1 or 2) of the telephone unit that picked up the handset.
(one of 0-7 assigned to a total of eight telephone units).

The extension call command has an operation code representing an extension call, and is generated by the caller when the extension call key 42 is pressed to start an extension call. In that case, the first operand is the number indicating one of the two inner lines (1 or 2) and the transmit modulation channel number (C
0-3) representing HO-CH3, and the second operand is the extension number of the called party (0-7>).

The extension callee response command is generated from the callee in response to the above-mentioned extension call command, and its operation code has a code indicating whether or not a call is possible. Its first operands are the extension number and receive demodulation channel number, and its second operand is the extension number of the called party that answers the call.

A hold command is generated from a telephone unit where a mid-call hold key 48 is pressed, which is used, for example, in a call transfer. The operation code has a code indicating a hold, the first operand is the extension number currently in use, and the second operand is the extension number of the telephone unit that placed the hold.

The transfer command is generated by operating the hold key, then keying the extension number of the transfer destination, and then the transfer source goes on-hook in a state where it is possible to talk to the transfer destination. The operation code has a code indicating whether it is an internal line transfer or an external line transfer. The first operand is the number of the internal line, and the second operand is the extension number of the transfer source in the case of an internal transfer, and the number of the external line of the call to be transferred in the case of an external transfer.

In addition to the above-mentioned commands, there is also a command that causes the extension line switching relay 94 to switch the extension line in use from one of the two to the other during an extension call. This can be used when one set of telephone units is in an internal call while another telephone unit initiates an external call over the same three internal lines. This is used when the signal level of the dial pulse is extremely high compared to the audio signal transmitted by FM carrier, and therefore there is a possibility that the audio signal may be interfered with by the dial pulse. This allows for simpler filtering within the circuit.

[Operation] Next, the operation of the telephone system according to the present invention is shown in FIGS. 6 and 7.
This will be explained with reference to the flowchart of FIG. 8 and FIG.

FIG. 6 is a flowchart showing the sequence when each telephone unit makes a call. First, in step 200, it is determined whether there is an extension call instruction by detecting whether the extension call key 42 has been pressed. If No, in step 202, the inner! The i/external line switching relay 84 is switched to the external line, and the external line switching relay 70 is switched to the appropriate line side. In the next step 204, the routine ends after calling the destination by dialing.

If YES in step 200, it is checked in step 206 whether all extension channels are used. This is microcomputer 11
This is possible by always keeping track of the usage status of extension channels.

If YES, in step 208, the microcomputer outputs a signal that generates a busy tone, and the routine ends.

If No, this indicates that there are extension channels that can be used, and in the next step 210, the extension channels to be used, such as CHOl and CHI, are determined. In step 212, the microcomputer outputs a signal to generate a dial tone, thereby indicating that the extension can be dialed.In step 214, the microcomputer checks whether the extension number has been keyed. If NO, loop to step 212.

If YES, the next step 216 is to send an extension calling command. This command uses the internal line number and the transmit modulation channel (for example, CHO) as the first operand.
), and the second operand includes the extension number of the called party (for example, 4 when calling from telephone unit 2 to telephone unit 4). This command is communicated to all telephone units.

Next, in step 218, it is determined whether the other party is on-hook. This is done by checking the extension ring optical response command received from the called party. This response command includes a code indicating whether the operation code is on-hook or off-hook, and the first operand is the number of the extension line and the number of the extension line. The second operand contains the extension number of the called party (eg 4). By checking this operation code and the second operand, it can be determined whether the other party is on-hook. If NO, the loop ends via step 208. If YES, the other party is on-hook, and in the next step 220, the microcomputer outputs a signal that generates a ringback tone to inform the caller that it is ringing.

The next step 222 checks to see if there is an off-hook command from the callee.

If NO, step 224 checks to see if the caller has gone on-hook; if NO, loops to step 220. If YES, it means that the call has been stopped and this routine ends. If YES in step 222, that is, if an off-hook command is received, the process proceeds to the next step 226. The off-hook command includes the extension number and reception demodulation channel (for example, CHI) in the first operand, and the called extension number (for example, 4) in the second operand.

In step 226, a C)(0 selection signal is output to modulation circuit 88, a CHI selection signal is output to demodulation circuit 90, and the circuits are turned on.

This opens the extension line and ends the routine.

Next, the sequence when called will be explained with reference to FIGS. 7 and 8. First, a call from an outside line to the slave telephone unit 22 shown in FIG. 7 will be explained. Note that calling to the master telephone unit 20 is the same as with a normal telephone;
Therefore, it will be omitted. In the first step 230, there is the input of a ringer command, ie a ringing signal to the slave. In the case of a call from an outside line, the master telephone unit 20 receives a ringer detection signal, while the slave telephone unit 22 receives a ringer command from the master telephone unit that detected the ringer signal.

In the next step 232, it is determined whether the self is off-hook. If YES, it is busy and the routine ends. If No, in step 234 the microcomputer outputs a signal that generates a ringing tone, and continues in the next step 236 until it detects that it is off-hook. When off-hook is detected in step 236, the internal line/external line switching relay 84 is switched to the external line side in step 238. Step 240
At , the outside line switching relay 70 is switched to the outside line side where the ringer is sounding, and this routine ends.

Next, a call from the extension shown in FIG. 8 will be explained.

In the first step 250, there is an input of an extension call command. This is the command sent in step 216 of FIG. In the next step 252, it is determined whether or not it is being called by checking the extension number (eg, 4) of the called party in the second operand of this command. If NO, this routine ends. If YES, the next step 254 is to check whether it is off-hook. If no, ie, off-hook, a step 256 sends an extension callee response command with an operation code indicating off-hook, and the routine ends.

On the other hand, if YES, in step 258, an extension called response command having an operation code indicating on-hook is sent.Next, in step 260, a signal to generate a ring tone is output, and in step 262, the own off-hook is sent. Continue until detected. If off-hook is detected, an off-hook command is sent in step 264. This command is the command examined in step 222 of FIG.
26, CHI! is sent to the modulation circuit 88. ! The selection signal is a ratio signal, the CHO selection signal is output to the demodulation circuit 90, and these circuits are turned on. This concludes this routine.

[Modification example] Although the multi-line telephone system, which is one embodiment of the present invention, has been described above, the following modifications can be made to this system. In the above embodiment, the ringer detection circuit was provided only in the master telephone unit in order to reduce costs.
It may be provided in the slave telephone unit if necessary.

In this case, the routine shown in FIG. 7 is not necessary.For primary channel multiplexing, in addition to the frequency modulation method, an amplitude modulation method, a phase modulation method, etc. can be used.

According to the telephone system of the present invention described in detail above,
Level switching makes it possible to make external calls and one extension call, although not at the same time, and in addition to level switching, providing an extension call channel different from the outside call channel makes it possible to make external calls and an extension call at the same time. Become. Furthermore, by multiplexing the extension call channels, multiple extension calls can be made simultaneously.

Thus, according to the present invention, it is possible to make an outside line call and an internal call on the same telephone line without deteriorating the sound quality, without using a conventional switchboard.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram showing the concept of the telephone system of the present invention. FIG. 2 is an overall configuration diagram of a multi-line telephone system that is an embodiment of the present invention. 3rd rI! i is a diagram showing the appearance of each telephone unit. FIG. 4 is a circuit diagram showing the circuit of the master telephone unit. FIG. 5 is a diagram showing the format of a command. FIG. 6 is a flowchart showing the flow when making a call. FIG. 7 is a flowchart showing the flow when receiving a call from an outside line. FIG. 8 is a flowchart showing the flow when receiving a call from an extension. FIG. 9 is a diagram showing an example of a multi-line telephone system using a conventional small-scale local exchange or key telephone system. (Explanation of symbols) 10: Multi-line telephone system, 12.14: Outside line, 16.18: Extension line, 20: Master telephone unit, 22 Nisle single telephone unit, 24: Phone jack, 30: Main unit, 31, Handset, 70 : External line switching relay, 84: Internal/external line switching relay, 88: Channel modulation circuit, 90: Channel demodulation circuit, 92 Nidorance, 94:
Extension switching relay, 102: Command modulation circuit, 104: Command demodulation circuit, 110: Microcomputer sleepover 2h')

Claims (5)

[Claims] (1) A) A common telephone line connected to the telephone line, B) Multiple telephones connected to the common telephone line, C) Each telephone is equipped with a A telephone system comprising: level switching means for switching the level of a signal sent from the telephone to the common telephone line. (2) In the telephone system according to claim 1, each of the telephones includes an audio signal transmitting/receiving means for transmitting and receiving audio signals, and an external line capable of communicating the audio signals in a first level range. a communication channel means for transmitting the audio signal to the first channel;
internal line communication path means capable of communicating in a second level range below a predetermined level lower than the level range; 2. A telephone system comprising: a telephone line switching means for connecting the voice signal transmitting and receiving means to the common telephone line via the extension telephone line during an extension telephone call. (3) In the telephone system according to claim 2, each of the telephones has switching control means for controlling internal calls and external calls of the telephone, and the extension communication path means: It has a plurality of extension communication channels different from the external communication channels of the external line communication path means, and the exchange control means is used for communication of exchange control signals at a level below the predetermined level between the plurality of telephones. Therefore, the telephone system has an exchange control communication channel different from the outside line communication channel, and uses this to specify a channel to be used among the plurality of extension communication channels when making an extension call. (4) The telephone system according to claim 3, wherein the plurality of extension communication channels and the exchange control communication channel are frequency multiplexed channels. (5) The telephone system according to claim 1, characterized in that there are two or more telephone lines.