JPS63222570A - Time division multiplex exchange - Google Patents

Abstract

PURPOSE:To eliminate a need for the use of an attenuation circuit by transmitting respective service tone signals in different levels but representing one service tone from a memory means, and transmitting it to a speech path highway through a time switch. CONSTITUTION:In the tone data memory 23 of a tone generation circuit 22, respective service tone signals representing various kinds of service tones are stored for cases where attenuation amount is 0dB, 3dB, and 6dB. The kinds of the service tone signals read out from the memory 23 depending on the output of a tone data kind counter 25 are sequentially changed corresponding to time slots, also, service tone signals are read out depending on the output of a tone data read counter 26 and transmitted to the time switch circuit 20 of a time switch part 18. Accordingly, attenuated service tone signals are transmitted out to the speech path highway 4, therefore, no attenuation circuits need to be used at the time of transmitting a service tone signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention is directed to a time division multiplexing system that transmits service tone signals to extension lines and central office lines at different levels.

(Prior Art) FIG. 4 is a block diagram showing a conventional digital key telephone 81 to which a time division multiplexing system is applied. In this digital button telephone device 1, a multi-function telephone I12 is connected to a communication highway 4 and a data highway 5 via a telephone interface unit 3, and a central office! ! ! 6 connects to the communication path highway 4 via the n-line interface unit 7.
and connected to Data Highway 5. The telephone interface unit 3 has an interface circuit 8, A
It is equipped with a /D converter 9 and a control circuit 10, and transmits and receives digitized voice signals to and from the communication highway 4, and transmits and receives data signals to and from the data highway 5.

Further, the office line interface unit 7 includes a line interface circuit 11, an A/D converter 12, and a control circuit 13, and transmits and receives digitized voice signals to and from the communication highway 4, and also transmits data to the data highway 5. Send and receive signals. The central processing unit 14 connected to the data highway 5 includes a central processing unit 15 and a RO'M 1.
6. Equipped with a RAM 17, which stores various data, as well as a telephone interface unit 3, a line interface unit 7, and a time switch section 18.
m.

On the communication path highway 4, audio signals sent and received to and from a plurality of telephone interface units and a plurality of office line interface units are time-division multiplexed and transmitted. The time switch unit 18 switches the time slots (temporal positions) of these audio signals.

The time switch section 18 also includes a tone sending section 19.
is connected, and this tone sending section 19 time-division multiplexes and sends out various digitized service tone signals indicating dial tones, visit tones, ringback tones, etc. A time switch circuit 20 in the time switch unit 18 inputs audio signals transmitted via each highway 4a, 4b, and 4C, and also inputs, for example, a diamond tone signal digitized from one tone sending unit to a time slot. Enter with TSO. Now, for example, when sending the dial tone signal of time slot TSO to time slot TS (m-2) of highway 4h, the time switch circuit 20 switches the dial tone signal of time slot TSO to time slot TS (m-2). and sends it to the downlink highway 4. As a result, from the downward communication route Highway 4, the time slot TS
A dial tone signal time-divided into (m-2) is sent to the time slot TS(m-2) of highway 4h.

On the other hand, for example, when transmitting the dial tone signal of time slot TSO to time slot TSm of highway 4j, the time switch circuit 20
After attenuating the dial tone signal by 6 dB via the attenuation circuit 21 connected to the time switch circuit 20,
The dial tone signal attenuated by 6 dB is switched to time slot TSm and sent to the downlink highway 4. As a result, a 6 dB attenuated dial tone signal time-divided into time slots TSm is transmitted from the downlink highway 4 to the highway 4j and the extension line connected to the time slot TSm.

The reason why the level of the service tone signal sent to the extension line is attenuated by 6 dB is because the level of the service tone signal set for the office line with a large amount of attenuation is too large for the extension line with a small amount of attenuation. It is for the purpose of passing it on. Similarly, the time switch circuit 20 is connected to the communication route highway 4.
The communication signal between the extension lines being transmitted through the attenuation circuit 21 is also attenuated by 6 dB.

However, in conventional time division multiplexing equipment,
As mentioned above, not only the call signals between extensions but also the service tone signals sent to the extensions are attenuated via the attenuation circuit, so this attenuation circuit is used more frequently and the attenuation circuit is There were times when the telephone line was blocked and calls between the extension number and extension ll1 could not be made.

(Problems to be Solved by the Invention) In this way, in the conventional time division multiplexing equipment, the service tone signal sent to the extension is attenuated via the attenuation circuit, so this attenuation circuit is blocked. There was a problem in that calls could not be made between extensions.

Therefore, in the present invention, when transmitting a service tone signal,
It is an object of the present invention to provide a time division multiplexing device that does not use an attenuation circuit.

[Structure of the invention]

(Means for Solving the Problems) The present invention connects a time switch to the communication highway for transmitting and receiving each signal to and from each line in each time slot, and the time switch transmits signals to the communication highway. In a time division switching device which switches the time slots of each time division multiplexed signal to switch and connect the lines, a memory in which service tone signals of different levels indicating the same service tone are stored in advance. means for transmitting each of the service tone signals of the different levels from the storage means to the time switch, and the time switch transmits each of the service tone signals to the communication highway in a predetermined time slot. It is characterized by

(Function) According to the present invention, service tone signals of different levels indicating the same service tone are sent from the storage means to the time switch, so that the time switch sends each service tone signal to a predetermined time slot. All you have to do is switch it over and send it to the communication highway, and no attenuation circuit is used at this time.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a tone generation circuit, a time switch section, etc. in a digital key telephone device to which an embodiment of the present invention is applied. The digital key telephone device of this embodiment is constructed by providing a tone generating circuit 22 in place of the tone sending section 8 in the device shown in FIG.

In FIG. 1, the same reference numerals are given to the parts having the same functions as those of the device shown in FIG. 4 for convenience of explanation.

In this embodiment, the tone data memory 23 in the tone generation circuit 22 stores each service tone signal representing various service tones at an attenuation of OdB.

The cases of 3 dB and 618 are stored respectively. These service tone signals are encoded signals of 8-bit codes formed by sampling analog signals representing service tones at a sampling frequency of 8 kHz and performing μ/L conversion. For example, as shown in FIG. 2, the dial tone signal has addresses "00" to "0(n-1)", 410, and
'' to ``1 (n-1)'' and ``20'' to ``2 (n-1)'', respectively.

Here, in the tone generation circuit 22, the signal output from the oscillation circuit 24 is counted by a tone data type counter 25 and a tone data read counter 26. In accordance with the output of the tone data type counter 25, the type of service tone signal read out from the tone data memory 23 is sequentially switched corresponding to the time slot.

Additionally, with the output of the tone data read counter 26,
A service tone signal is being read out from the tone data memory 23. Various service tone signals read from the tone data memory 23 are subjected to parallel/serial conversion by a parallel/serial converter 27, and sent to the time switch circuit 20 in the time switch section 18 as a time division multiplexed signal. For example, attenuation amount QdB, 3
The dB and 8 dB dial tone signals are transmitted to the time switch circuit 20 in each time slot TSO, TS1 and TS2, respectively.

On the other hand, a table as shown in FIG. 3 is stored in advance in the microprocessor 29 connected to the central processing unit 14. This table shows the attenuation ff1OdB for each time IPJO~1 connected to the communication path highway 4.
, 3dB and 6dB dial tone signals to be sent. That is, for example, for line O, a bit "1" indicating a dial tone signal with an attenuation of 16 dB is stored. Such a table is necessary because the digital button telephone device 1 employs a flexible boat. Note that the flexible boat is capable of mounting various interface units in each time slot of the communication channel highway 4 at any ratio.

Now, in FIG. 1, when sending a dial tone signal to the highway 4h connected to the local office line on the downlink highway 4, the microprocessor 29, based on the fact that the highway 4h is connected to the local office line, A dial tone signal with an attenuation of 10 dB is determined by reading the bits for the office line from the table shown in FIG. 3, and based on this determination, the time switch circuit 20 is controlled via the microcomputer interface 28.

In response, the time switch circuit 20 switches the dial tone signal with the attenuation amount 06B sent from the tone generation circuit 22 in the time slot TSO to the time slot TS (m-2> of the highway 4h) and transmits it to the downlink highway 4. As a result, the downstream communication route Highway 4
From there, a dial tone @ with an attenuation of 10 dB, which is time-divided into time slots TS<m-2), is sent to the office line connected to the highway 4h.

Furthermore, when sending a dial tone signal to the highway 4j connected to the extension on the downlink highway 4, the microprocessor 29 uses the table shown in FIG. 3 based on the fact that the highway 4j is connected to the extension. A dial tone signal with an attenuation of 16 dB is determined by reading the bits for the extension from , and based on this determination, the time switch circuit 20 is controlled via the microcomputer interface.The time switch circuit 20 responds to this. Then, the 6 dB dial tone signal sent from the !--tone generating circuit 22 in the time slot TS2 is switched to the time slot TSm of the downlink highway 4j and sent out to the downlink highway 4. As a result, a dial tone signal with an attenuation fa of 6 dB, which is time-divided into time slots TSm, is sent from the downlink highway 4 to the extension line connected to the highway 4j.

In this manner, in this embodiment, the attenuated service tone signal sent from the tone generation circuit is sent out to the communication highway via the time switch, so that there is no need to use an attenuation circuit when sending out the service tone signal.

Although this embodiment exemplifies a digital key telephone device, the present invention is not limited to this, and can also be applied to, for example, a time division multiplexing type private branch exchange.

〔Effect of the invention〕

As explained above, according to the present invention, each service tone signal at a military level indicating the same service tone is sent out from the storage means, and these service tone signals are sent out to the communication highway via a time switch. Therefore, it is possible to provide a time division multiplexing device that does not use an attenuation circuit when transmitting service tones.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a tone generation circuit, a time switch section, etc. in a digital button telephone device to which an embodiment of the present invention is applied, and FIG. 2 is a storage of tone data memory in the tone generation circuit shown in FIG. 3 is a diagram showing the table stored in the microprocessor shown in FIG. 1, FIG. 4 is a block diagram showing a conventional digital button telephone device, and FIG. FIG. 2 is a block diagram showing a tone sending unit, a time switch unit, etc. in the conventional coin shown in FIG. DESCRIPTION OF SYMBOLS 1...Digital button telephone device, 2...Multifunction telephone, 3...Telephone interface unit, 4...
・Call route highway, 5...Data highway, 6.
... Office line, 7... Office line interface unit, 14
... central processing unit, 18 ... time switch section, 20 ... time switch circuit, 21 ... attenuation circuit, 22 ... tone generation circuit, 23 ... tone data memory, 24 ... Oscillation circuit, 25... Tone data type counter, 26... Tone data read counter, 27... Parallel/serial converter, 28... Microcomputer interface, 29... Microprocessor. Fig. 2 Fig. 3 ± Teji71shichitarejicoat Fig. 4

Claims (1)

[Scope of Claims] A time switch is connected to a communication highway for transmitting and receiving each signal to and from each line in respective time slots, and the time-division multiplexed signals are transmitted to the communication highway by the time switch. A time division multiplexing device configured to switch and connect the respective lines by switching the time slots of each signal, comprising a storage means in which service tone signals of different levels indicating the same service tone are stored in advance, and the storage means The time-sharing system is characterized in that the means sends each of the service tone signals of different levels to the time switch, and the time switch sends each of the service tone signals to the communication highway in a predetermined time slot. Multiple exchange device.