JPH08274889A - Transmitter - Google Patents

Abstract

PURPOSE: To surely form a transmission line while reducing the degradation of transmission quality for the combination of a compression encoding system. CONSTITUTION: This transmitter is provided with a code decoding means 11 for converting and absorbing the difference of the forms of speech signals when the logic value of a command is specified between a direction and an inter-office transmission line whose bit rate is different from it, a bit rate adjustment means 13 for adding or eliminating dummy bits to/from the speech signals and absorbing the difference of the bit rate between the direction and the inter-office transmission line when the logic value takes an opposite value, a compression transmission system informing means 15 for being supplied with the identification information of the compression transmission system of the inter-office transmission line and adding the identification information to the speech signals sent out to the direction from the code decoding means 11 and the bit rate adjustment means 13 and a relay mode discrimination means 17 for discriminating the difference and omission of the identification information added to the speech signals from the direction and the identification information of the compression transmission system capable of being absorbed by the bit rate adjustment means 13 and attaining the command.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device for forming a transmission line applied to a desired compression coding system between stations of a telephone network to which a compression coding transmission system is applied.

[0002]

2. Description of the Related Art In recent years, techniques relating to voice compression coding transmission have made remarkable progress, and many branch line transmission lines connecting business establishments of enterprises to each other are being formed through an integrated digital network. . In addition, the optimum compression coding method is applied to each of these branch line transmission lines at the time of installation, and the compression ratio is set between the caller side subscriber line exchange and the callee side subscriber line exchange. In order to form a communication path via a plurality of relay sections having different compression ratios, a transmission path for performing conversion processing between compression coding systems having different compression ratios is arranged for each transmission section.

FIG. 7 is a diagram showing a configuration example of a conventional transmission device. In the following, for simplification, a specific outgoing path (or incoming path) formed between the adjacent station and a plurality of incoming and outgoing paths of the exchange with a known compression ratio. Only the explanation will be given. In the figure, the output of the above-mentioned specific outgoing path (incoming path) is connected to the common contact of the switch 81 ₁ , and _one contact of the switch has a compression encoding unit 82.
Is connected to one contact of the switch 81 ₂ . The other contact of the switch 81 ₁ is directly connected to the other contact of the switch 81 ₂ , and the common contact of the switch is connected to the downlink transmission path corresponding to the above-mentioned specific output path (input path). An upstream transmission line paired with such a downstream transmission line is connected to a common contact of the switch 83 ₁ , and _one contact of the switch is connected to one contact of the switch 83 ₂ via the compression decoding unit 84. . The other contact of the switch 83 ₁ is directly connected to the other contact of the switch 83 ₂ , and the common contact of the switch is connected to the input of the above-mentioned output path (input path). Since the compression encoding unit 82 and the compression decoding unit 84 form an integrated codec, the codec "85" is attached to the codec below.

Conventionally, for example, as shown in FIG.
From the exchange 91 accommodating the caller to the transit exchange 9
2₁, 92₂To the exchange 93 in which the called party is accommodated via
In the reaching section, the transmission device 9 having the above-described configuration is provided for each relay section.
4₁₁, 94₁₂, Transmission device 94_{twenty one}, 94_{twenty two}, Transmission device 94
₃₁, 94₃₂Are arranged to face each other. In addition,
The first compression encoding method applied to these relay sections (see
Here, for simplicity, the compression ratio is "8" and the bit rate is
It is assumed that the rate is 8 kbps. ) Are all the same
Is the transmission device 94 closest to the exchanges 91, 93.₁₁, 9
4 ₃₂Then, under the preset settings of the transmitter,
Switch 81₁, 81₂And switch 83₁, 83₂Common contact with
Each point is connected to one contact and the other in the other
Remaining transmission device 94 forming a joint section₁₂, 94_{twenty one}, 94
_{twenty two}, 94₃₁Now, under the same setting, switch 81₁, 8
1₂And switch 83₁, 83₂Each has a common contact with
Connected to one contact.

That is, in the transmission devices 94 ₁₁ and 94 ₃₂ ,
Each of the codecs 85 performs coding / decoding based on the first compression coding method, and the other transmission devices 9
4 ₁₂ 94 _21, 94 _22, in 94 _31, the relay of such encoding-decoding via a repeater section which precedes without performing signal received based on the encoding-decoding method is performed. Further, for example, as shown in FIG. 8 (b), the transmission apparatus 94 ₂₁ -
A second compression encoding method different from the first compression encoding method described above in the relay section sandwiched by 94 ₂₂ (here, the compression ratio is “4” and the bit rate is 16 kbps for simplicity. In the case of these transmission devices, the common contacts of the switches 81 ₁ and 81 ₂ and the switches 83 ₁ and 83 ₂ are respectively connected to one of the contacts under the same settings. A codec 85 adapted to the second compression coding system is arranged. Further, in the transmission devices 94 ₁₂ and 94 ₃₁ , under the same setting, the common contacts of the switches 81 ₁ and 81 ₂ and the switches 83 ₁ and 83 ₂ are connected to one contact, respectively, and the codec 85 has the first contact. Applies to compression coding method.

That is, decoding and coding based on each compression coding method are repeatedly performed for each relay section,
Switch 91, 93 and the relay switch 92 _1, 92 _2,
In each case, circuit switching is performed for each primary group of PCM signals (given by a 64 kbps bit string) generated based on such decoding.

[0007]

However, in the transmission line to which such a conventional transmission device is applied, when the compression coding method applied to all the relay sections from the exchange 91 to the exchange 93 is not the same. In the above, since the decoding and the coding are repeatedly performed for each relay section, the quantization error associated with each decoding and coding is accumulated in each relay section, and the transmission quality is deteriorated.

As prior art similar to the present application, for example, Japanese Patent Laid-Open No. 6-030141 and Japanese Patent Application No. 5-14.
There is one described in No. 8789. However, in these prior arts, the bit rate of the relay section directly connected to both ends of the transmission line is 8 kbps, and the bit rate of the relay section sandwiched between other relay sections is 16 kbps, When the bit rate of the relay section is 8 kbps and the bit rate of all subsequent relay sections is 16 kbps, there is a high possibility that the transmission quality of voice will deteriorate,
In some cases, the transmission path could not be formed normally.
Furthermore, such deterioration of transmission quality becomes remarkable when the statistical properties are different from those of voice, such as in a facsimile signal. Actually, the bit rate of the relay section directly connected to both ends of the relay section is 16 kbps. It could not be applied except when the bit rate of other relay sections was 32 kbps.

It is an object of the present invention to provide a transmission device capable of reliably forming a transmission path while reducing the deterioration of the transmission quality regardless of the combination of compression coding methods applied to individual relay sections. And

[0010]

FIG. 1 is a block diagram showing the principle of the invention described in claims 1 to 3.

The invention according to claim 1 is arranged between an ingress path and an egress path of the exchange and an inter-station transmission path to which a compression coding transmission system having a different bit rate is applied.
When the input binary command takes a specific logical value, the code decoding means 11 that absorbs the difference in the format of the call signal between the two by converting the format, and the command has a specific logical value. Bit rate adjustment that absorbs the difference in bit rate by inserting or developing a dummy bit in the call signal transmitted and received between the inbound or outbound path and the interoffice transmission line when taking a logical value different from Means 13
And the identification information indicating the compression coding transmission method applied to the inter-station transmission path is given in advance, and the call transmitted from the coding / decoding means 11 and the bit rate adjusting means 13 toward the inbound path or the outbound path. The compression transmission method notifying means 15 for adding the identification information to the signal and the identification information of the compression coding transmission method by which the bit rate adjusting means 13 can absorb the difference in the bit rate are given in advance, and these identification information are input. Relay mode discriminating means 1 for discriminating the difference between the discrimination information added to the call signal given from the route or the outgoing route and the presence or absence of the lack of the discrimination information, and outputting the discrimination result as a command.
7 is provided.

According to a second aspect of the present invention, in the transmission apparatus according to the first aspect, the relay mode discriminating means 17 outputs the call signal sent from the bit rate adjusting means 13 toward the inter-station transmission path. The relay mode notifying means 21 for adding the command to send to the inter-station transmission path is provided, and the bit rate adjusting means 13 combines the call signal received via the inter-station transmission path with the call signal. The compression transmission system notifying means 15 includes means for transmitting the added command to the compression transmission method notifying means 15, and the compression transmission method notifying means 15 includes the bit rate adjusting means 1.
Means for adding the command transmitted by the bit rate adjustment adjusting means to the call signal transmitted from 3 to the incoming route or the outgoing route in combination with the identification information given in advance or in place of the identification information. It is characterized by including.

According to a third aspect of the present invention, in the transmission apparatus according to the first or second aspect, the relay mode discriminating means 17 measures the length of a period in which identification information is not added to the call signal, When the length of the period exceeds a threshold value set in advance to a value equal to or greater than the reciprocal of the minimum response speed of the exchanges facing each other through the incoming route or the outgoing route, if the identification information of the different discrimination target is different. It is characterized in that it includes means for observing.

[0014]

In the transmission device according to the invention described in claim 1, when it is directly connected to the outgoing path of the exchange, the compression transmission system is applied to the subscriber circuit connected to the outgoing path and the communication path. The means corresponding to the notification means 15 is not included. Therefore, for a call signal given from such an outgoing route, the bit rate adjusting means 13 is used for the outgoing route among the compression coding transmission systems applicable to the inter-station transmission line directly connected to the outgoing route. However, it does not include any identification information, although it can absorb the difference in bit rate between the two. Relay mode discrimination means 1
When detecting the lack of the identification information to be added to the call signal given from the outgoing route in this way, 7 outputs a command to take a specific logic to that effect. Code decoding means 11
Responds to such a command by absorbing the above-mentioned difference in the format of the call signal between the outgoing route and the interoffice transmission line by converting the format.

Further, the relay points facing each other via the inter-station transmission path and the relay points subsequent to the relay points, which are arranged so that the bit rate of the directly connected relay section is equal to or higher than the above-mentioned bit rate. In that case, between the compression transmission system notifying means 15 and the relay mode discriminating means 17, which are opposed to each other via the exchanges arranged at the respective relay points,
Identification information of the compression coding transmission method applied to the relay section directly connected to the corresponding relay point is added to the call signal and transmitted / received.

Further, the relay mode discriminating means 17 uses the identification information thus obtained as the bit rate adjusting means 1.
Since 3 matches the identification information of the compression coding transmission method capable of absorbing the difference in bit rate, a command of a logical value different from the above-mentioned specific logical value is transmitted. In response to such a command, the encoding / decoding means 11 is suspended, and the bit rate adjusting means 13 is transmitted / received to / from an adjacent relay section which individually corresponds to an incoming route and an outgoing route of the exchange. The bit rate difference is absorbed by performing dummy bit insert and development on the signal.

That is, to the subscribers facing each other through a plurality of relay sections to which different compression coding transmission systems are applied,
Encoding and decoding are performed respectively only at one end of the relay section closest to the exchanges accommodating these subscribers,
In the relay section sandwiched between the other ends of these relay sections, the transmission path is reliably provided by simply absorbing the difference in bit rate between the adjacent relay sections.

Therefore, the deterioration of the transmission quality due to the repeated compression encoding and compression decoding for each relay section can be avoided. In the transmission device according to the second aspect of the present invention, the relay mode notifying means 21 is sent from the bit rate adjusting means 13 toward the inter-station transmission path when it is arranged at both ends of the inter-station transmission path. The command output from the relay mode discriminating means 17 is added to the call signal, and the call signals are mutually sent to the opposite transmission devices via the inter-station transmission path.

Further, in these transmission devices, the bit rate adjusting means 13 sends the command added to the call signal to the compression transmission system notifying means 15 in addition to the call signal received via the inter-station transmission path. introduce. The compression transmission system notifying means 15 gives the transmitted signal to the exchange by adding the transmitted command to the call signal in combination with the given identification information or in place of the identification information.

That is, different compression coding transmission systems are applied to the relay section connected to the incoming route of the exchange containing the callee and the relay section connected to the outgoing route of the exchange containing the caller. If a transmission device other than the transmission device according to the present invention is arranged at any of the relay points forming a transmission line sandwiched between these relay sections, it is possible to adjust the bit rate only. The fact that the relay cannot be performed is sequentially and reliably transmitted to the transmission device at the relay point preceding the relay section.

Accordingly, the combination of the compression coding transmission method applied to each relay section and the existing transmission network in which the transmission device according to the present invention is not arranged are adapted to the encoding and decoding for each relay section. The relay is surely performed by performing and. In the transmission device according to the present invention as defined in claim 3, the relay mode determination means 17 measures the length of a period during which no identification information is added to the call signal, and the length of the period faces the exchange device via the exchange. When the threshold value set in advance to a value equal to or greater than the reciprocal of the minimum response speed of is exceeded, it is considered that the identification information as the different determination target is different.

Therefore, even under the condition that the transmission device according to the present invention is arranged on the outgoing route or incoming route of the exchange accommodating the caller or the callee and the identification information is not given from the exchange, The rate adjusting means 13 is set to a dormant state, and the code decoding means 11 absorbs the difference in the format of the call signal between these routes and the interoffice transmission line by converting the format. Can be done reliably.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.
Will be described in detail. FIG. 2 shows the invention according to claims 1 and 3.
FIG. 6 is a diagram showing a configuration and an operation of an embodiment corresponding to. Figure
At the outgoing route of the exchange 31 accommodating the caller
The transmission device 32 according to the invention of item 1.₁₁(Hereinafter, the same
Thus, the transmission device according to the invention of claim 1 is provided.
Is denoted by reference numeral “32”. ) Via Bitray
Is connected to one end of the first relay section, which is 8 kbps.
The other end of the first relay section is the transmission device 32.₁₂Through
Relay switch 33₁Of the transit exchange connected to the
The outgoing route is the transmission device 32_{twenty one}Bit rate through 16kbps
Is connected to one end of the second relay section. The second
The other end of the relay section is the transmission device 32._{twenty two}Relay exchange 3 via
Three ₂Connected to the incoming route of the
Sending device 32₃₁Via the third bit rate is 8kbps
Is connected to one end of the relay section. Of the third relay section
The other end is a transmission device 32₃₂A switchboard that accommodates the called party via
It is connected to 34 entrance routes.

FIG. 3 is a diagram showing a configuration of transmission devices arranged at both ends of the first and third relay sections. In the figure, the output of the exchange is connected to the input of the frame detector 41, and the output of the frame detector 41 is the switch 42 ₁
Connected to the common contact of. One contact of the switch 42 ₁ is connected to one contact of the switch 42 ₂ via the compression unit 43, and the common contact of the switch 42 ₂ is connected to the input of the transmission line. The bit removing unit 44 is arranged between the other contact of the switch 42 _{1 and} the other contact of the switch 42 ₂ . The output of the transmission line is connected to the common contact of the switch 45 ₁ , and one terminal of the switch is connected to one contact of the switch 45 ₂ via the bit adding section 46. The common contact of the switch 45 ₂ is connected to the input of the exchange through the frame addition section 47. The other contact of the switch 45 ₁ is connected to the other contact of the switch 45 ₂ via the decoding unit 48. The control output of the frame detector 41 is connected to the control inputs of the switches 42 ₁ , 42 ₂ , 45 ₁ , 45 ₂ .

FIG. 4 is a diagram showing the configuration of the transmission devices arranged at both ends of the second relay section. In the figure, those having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here. The difference between the configuration of the transmission apparatus shown in FIG. 4 and the configuration of the transmission apparatus shown in FIG. 3 is that a compression unit 51 is provided instead of the compression unit 43, a decoding unit 52 is provided instead of the decoding unit 48, and frame detection is performed. The point is that a frame detection unit 53 is provided instead of the unit 41.

Regarding the correspondence between this embodiment and the block diagram shown in FIG. 1, the compression units 43 and 51 and the decoding units 48 and 52 correspond to the encoding / decoding means 11, the bit removing unit 44 and the bit adding unit. The unit 46 is a bit rate adjusting unit 1.
3, the frame addition unit 47 and the frame detection unit 55 correspond to the compression transmission system notification unit 15, the frame detection unit 53 corresponds to the relay mode determination unit 17, and the frame addition unit 54 corresponds to the relay mode notification unit 21. Correspond.

The operation of this embodiment will be described below with reference to FIGS. For the sake of simplicity, the exchange 31
And between the switch 34 shall selection of route through the first to third repeating section described above and the transit exchange 33 _to 333 ₂ is completed. In the transmission device 32 ₁₁ , the compression unit 43 applies the compression coding method adapted to the first relay section, and the decoding unit 48 applies the compression decoding method adapted to the compression coding method. In addition, the frame addition unit 47
Is a plurality of octets that are provided with identification information indicating such a compression coding method in advance and that form a PCM signal transmitted from the bit adding unit 46 or the decoding unit 48 to the exchange 31 via the switch 45 _2. LSB (or MSB) of 8Nth octet for integer N
As a result, a frame synchronization signal F1 indicating the identification information is added (FIG. 2 (1), FIG. 5 (a)).

The exchange 31 takes in a PCM signal including such a frame synchronization signal F1 and gives it to the caller's terminal through the communication path formed by the circuit switching system. Regarding the voice signal sent from the terminal, Predetermined PCM
It is converted into a signal and given to the transmission device 32 ₁₁ via the same speech path. In the transmission apparatus 32 _11, frame detection unit 41, a single or a plurality of identification information indicating individually all compression coding method bit removing unit 44 and the decoding unit 48 are applicable is given in advance, like this It is monitored whether or not any frame synchronization signal is received in the PCM signal based on the format shown in FIG. 5 (a). However, as described above, the PCM signal provided from the exchange 31 does not include a frame synchronization signal corresponding to any of these pieces of identification information, so the frame detection unit 41 recognizes that fact by such monitoring. Switch 42 ₁ , 42 ₂ , 4
The common contact of 5 ₁ and 45 ₂ is connected to each one contact.

In such a state, the PCM signal output from the exchange 31 is given to the compression unit 43 via the frame detection unit 41 and the switch 42 ₁ . Compression unit 43
Has a bit rate of 8 kb by compressing and coding the PCM signal provided in this way with a compression ratio of "4".
It is converted into a code string of ps (Fig. 5 (b)) and sent to the first relay section. Further, the code string given from the transmission device 32 ₁₂ facing the other side via the first relay section is given to the decoding unit 48 via the switch 45 ₁ , and the decoding unit 48 decodes such a code string. Bit rate is 64kbps
Is generated, and the PCM signal is given to the exchange 31 via the switch 45 ₂ and the frame adding section 47.

In the transmission device 32 ₁₂ , the compression coding method adapted to the first relay section is applied to the compression section 43, and the compression decoding method adapted to the compression coding method is applied to the decoding section 48. It Further, the frame addition unit 47 is previously provided with identification information indicating such a compression encoding method,
From the bit adding unit 46 or the decoding unit 48 to the switch 45
PCM sent to the repeater exchange 33 ₁ via ₂
Of a plurality of octets forming a signal, a frame synchronization signal F1 indicating its identification information is added as an LSB (or MSB) of the 8Nth octet with respect to an integer N.
(FIG. 2 (2), FIG. 5 (c)).

Relay switch 33₁A frame like this
Circuit switching method by taking in PCM signals including sync signal F1
Connected to the outgoing route via the speech path formed by the formula
Transmission device 32_{twenty one}Give to. Transmission device 32_{twenty one}Then the compression section
A compression coding method adapted to the second relay section is suitable for 51.
Used for the decoding unit 52 and adapted to the compression encoding method.
A compression decoding method is applied. In addition, the frame addition unit 4
7, the identification information indicating such a compression coding method is previously stored.
Given from the bit adding unit 46 or the decoding unit 52.
Switch 45 ₂Through the exchange 33₁Should be sent to
Of the multiple octets that make up the CM signal, the integer N
Then, the frame showing the identification information in the 8th octet
A frame synchronization signal F0 is added (FIG. 2 (3), FIG. 5 (c)).

The relay exchange 33 ₁ takes in the PCM signal including the frame synchronization signal F0 and gives it to the transmission device 32 ₁₂ corresponding to the incoming route via the speech path formed by the circuit switching system. On the other hand, in the transmission apparatus 32 ₁₂ , when the frame detection unit 41 receives the frame synchronization signal F0 from the transmission apparatus 32 ₂₁ via the transit exchange 33 ₁ in this way, the frame synchronization signal is assumed in advance as described above. All of the compression encoding methods that have been performed are compared with identification information that indicates individually, and if any of these identification information is applicable, the common contact of the switches 42 ₁ , 42 ₂ , 45 ₁ , 45 ₂ is individually connected to the other contact. Connecting.

Further, the transmission device 32_{twenty one}Then, frame inspection
The output unit 53 is similar to the transmission device 32.₁₂From transit switch
33₁When the frame synchronization signal F1 is given via
The frame sync signal was previously assumed as described above.
Compare all compression coding schemes with identification information that shows individually,
If any of these identification information is applicable, the switch 4
2 ₁, 42₂, 45₁, 45₂The common contacts of the
Connect to a point.

In such a state, the signal received from the first relay section in the transmission device 32 ₁₂ is the switch 4
5 ₁ to the bit adding unit 46, which adds a dummy bit to convert the bit rate to 64 kbps, and supplies it to the transit exchange 33 ₁ via the switch 45 ₂ and the frame adding unit 47. . The transit exchange 33 ₁ transmission apparatus 32 ₂₁ gives PCM signal provided in this manner via the speech path, the transmission apparatus 32 _21, bit removing unit supplies the PCM signal via a frame detection unit 53 and a switch 42 ₁ 44. The bit remover 44 is thus provided to the PC
After taking in the M signal and removing the dummy bit corresponding to the difference in bit rate from the second relay section among the dummy bits included in the PCM signal, the dummy bit is transferred to the second relay section via the switch 42 _2. Send out.

Further, the transmission device 32_{twenty one}Second relay
The signal received from the section is the switch 45.₁Through
Given to the bit addition unit 46, and the bit addition unit is a dummy.
Bit rate is increased to 64 kbps by adding bits
Convert and switch 45₂And through the frame adding unit 47
And relay switch 33₁Give to. Relay switch 33₁Hako
The PCM signal transmitted as described above is transmitted through the communication path.
Sending device 32₁₂To the transmission device 32₁₂Then the PCM
The signal is the frame detection unit 41 and the switch 42. ₁Through
Are provided to the bit removing unit 44. Bit removing unit 44
Takes the PCM signal applied via
Of the dummy bits included in the PCM signal.
A dummy corresponding to the difference in bit rate from one relay section
Remove bits (Fig. 5 (d)) and switch 42₂Through
To the first relay section of.

Further, the transmission device 32 ₂₂ , the relay exchange 33 ₂ , the transmission device 32 ₃₁ , and 3 which face each other across the second relay section.
2 ₃₂ and the exchange 34, the configuration of the relay section sandwiched between the exchange 31 and the switch 34 and the compression coding method applied to each relay section are symmetrical with respect to the second relay section. , Transmission devices 32 ₂₁ , respectively,
The operations are the same as those of the relay exchange 33 ₁ , the transmission devices 32 ₁₂ and 32 _11, and the exchange 31, and the description thereof is omitted here.

As described above, according to the present embodiment, the transmission devices 32 ₁₁ and 32 ₃₂ connected to the outgoing paths of the exchanges 31 and 34 accommodating the caller and the callee do not receive the synchronization signal. By recognizing, it is detected that there is no transmission device facing each other through these exchanges, and the compression encoding process and the compression decoding process are performed. Also,
In each relay section sandwiched between these transmission devices, the transmission devices 32 facing each other with the intermediary exchanges 33 ₁ and 33 ₂ sandwiched therebetween.
₁₂ and 32 ₂₁ and the transmission devices 32 ₂₂ and 32 ₃₁ transmit and receive mutually known synchronization signals so that decoding and encoding are unnecessary even when the bit rates of adjacent relay sections are different. It recognizes and absorbs the difference between the bit rates of these relay sections and the bit rates of the speech paths formed in the transit exchange.

Therefore, in order to absorb the difference in the compression encoding method, the decoding and the encoding which have been performed for each relay section in the conventional example are omitted, and the voice is reliably transmitted across these relay sections. A possible digital transmission path is formed, and deterioration of transmission quality accumulated for each relay section due to such decoding and encoding is avoided. Regarding the combination of compression coding methods applied to each relay section, the bit removal section 44 and the bit addition section 46 can reliably absorb the difference in bit rate between the exchange (relay exchange) side and the relay section. , And the compression encoding method applied to the outgoing route of the exchange that accommodates the caller and the incoming route of the exchange that accommodates the callee are the same. If all the transmission devices connected to each relay section up to are related to the present invention,
It may be anything.

FIG. 6 is a diagram showing the configuration and operation of an embodiment corresponding to the invention described in claims 2 and 3. In the figure, components corresponding to those shown in FIG. 2 are designated by the same reference numerals, and description thereof will be omitted here.
The difference between the present embodiment and the embodiment shown in FIG. 2 is that the exchange 34 accommodating the called party is connected via the transmission device 32 ₂₂ immediately after the second relay section.

Further, in this embodiment, the transmission devices 32 ₂₁ , 3
2 _22, as shown by the dotted line in FIG. 4, the common contact of the switch 42 ₂ is connected to the second repeating section through the frame addition unit 54, via the frame detector 55 to the common contact of the switch 45 ₁ Connected to the second relay section, the control output of the frame detection unit 53 and the control output of the frame detection unit 55 are connected to the reset input and the activation input of the timer 56, respectively, and the output of the timer is added to the frame addition unit 54. It is configured to be connected to the control input of.

The operation of this embodiment will be described below with reference to FIGS. In addition, from the exchange 31 to the relay exchange 33 ₁
The operation of each part in the section up to and the format of signals transmitted and received between each transmission device and the relay section and the exchange (including the relay exchange) (including the format of each frame synchronization signal described later) are described above. Since it is the same as the embodiment corresponding to the invention described in claim 1, the description thereof is omitted here.

In the transmission device 32 ₂₁ , the frame addition unit 54
Takes in a code string (including dummy bits and has a bit rate of 16 kbps) given from the repeater exchange 33 ₁ through the frame detector 53, the switch 42 ₁ , the bit remover 44 and the switch 42 ₂ , and the A frame synchronization signal F2 having a bit pattern different from any of the frame synchronization signals F0 and F1 described above is added to the code string and transmitted to the second relay section (FIG. 6 (1)).

On the other hand, in the transmission device 32 ₂₂ , the frame detection unit 55 takes in the code string received through the second relay section and puts the above-mentioned frame synchronization signal F2 in the code string.
Is included, and if the frame synchronization signal is included, the timer 56 is started. In addition, the frame adding section 47 is a code string (the bit rate is converted to 64 kbps) given through the frame detecting section 55, the switch 45 ₁ , the bit adding section 46 and the switch 45 ₂ in this way. A frame synchronization signal F0 is added and sent to 34 (FIG. 6 (2)).

However, the frame detecting section 53 is
Since 4 does not have an outgoing route which accommodates the called party and is connected to the subsequent relay section, and a transmission device corresponding to the outgoing route,
No frame sync signal in response to the frame sync signal F0 described above can be detected. Therefore, timer 5
6 accumulates the time elapsed from the above-mentioned start-up time,
When the time exceeds the maximum allowable time until the frame sync signal in response to the frame sync signal F0 described above is detected, the fact is notified to the frame addition unit 54. Frame addition unit 54, the transmission apparatus 32 ₂₁ to face each other with a second repeating section in response to such a notification, and sends the frame synchronization signal F2 'in response to the frame synchronization signal F2 as described above (FIG. 6 ( 3)).

In the transmission device 32 ₂₁ , the frame detector 55
Monitors whether or not such a frame synchronization signal F2 'is received through the second relay section, and if received, the switch 45 ₁ , the bit adding unit 46 and the switch 4 are received.
5 ₂ via notifies the frame addition unit 47.
Frame addition unit 47, instead of the frame synchronization signal F0 described above to recognize such notification, the description of the frame synchronization signals F0, F1, F2, F2 'any different frame synchronization signal F0 also of' the transit exchange 33 ₁ (FIG. 6 (4)).

Such a frame synchronization signal F0 'is relayed.
Switch 33₁Via the transmission device 32 ₁₂Frame detector
The frame detector 41 is provided to the frame detector 41 (FIG. 6 (5)).
Indicates that the frame sync signal is the same as the predetermined frame.
Any of the synchronization signals (for example, the frame synchronization signal F1).
Therefore, based on the frame synchronization signal F0 transmitted earlier,
Switch 42.₁Four
2₂, 45₁, 45₂Connect the common contact of
It Therefore, the transmission device 32₁₂Then, the first relay section
Decoding by the decoding unit 48 for signals transmitted and received via
The encoding process and the encoding process by the compression unit 43 are performed. Well
In such a state, the decoding performed by the decoding unit 48 is
The PCM signal given by
Relay switch 33 ₁Given to.

In the transmission device 32 ₂₁ which faces the relay switch 33 ₁ , the frame detector 53 cannot detect the frame synchronization signal F1 and the switches 42 ₁ , 4
The common contact of 2 ₂ , 45 ₁ and 45 ₂ is connected to one contact. Therefore, in the transmission device 32 ₂₁ , the decoding process by the decoding unit 52 and the coding process by the compression unit 51 are performed on the signal transmitted / received via the second relay section.

As described above, according to this embodiment, the compression coding method applied to the relay section directly connected to the outgoing route or incoming route of the exchange accommodating the caller and the callee is different, or It is smoothly detected that the transmission device according to the invention of claim 1 or 2 is not present on the transmission line formed between the exchanges, and the decoding and encoding are performed for each relay section. By repeating, the transmission line is surely formed.

In each of the above embodiments, the switch 4
2 ₁ and 42 ₂ are arranged at the input / output ends of the compression unit 51 and the bit removal unit 44, respectively, and switches 45 ₁ and 45 ₂ are arranged at the input / output ends of the decoding unit 48 (52) and the bit addition unit 46, respectively. However, the present invention is not limited to such a configuration. For example, the compression unit 51, the bit removal unit 4
4, the decoding unit 48 (52) and the bit addition unit 46 operate in opposition to each other under the control signal provided by the frame detection unit 53, and the output impedance in the idle state is compared to the other output impedance in operation If the outputs are sufficiently high, it is possible to directly connect these outputs without using the switches 42 ₂ and 45 ₁ , and the compression unit 51, the bit removal unit 44, and the decoding unit 48.
If the input impedances of (52) and the bit addition section 46 are both sufficiently high and neither of them significantly fluctuates during operation and at rest, these inputs are directly connected without using the switches 42 ₁ and 45 ₂ . It can also be configured.

In each of the above embodiments, the exchange 3
The bit rates of the outgoing routes and incoming routes of ₁ , 34 and the repeater exchanges 33 ₁ , 33 ₂ are 64 kbps,
The present invention is not limited to such a configuration, and may be any bit rate as long as it is equal to or lower than the bit rate of the compression coding transmission system applied to the relay section directly connected to these outgoing routes and incoming routes. And the bit rate may be different for each exchange arranged at each relay point.

Further, in each of the above-described embodiments, the frame adding section 54 and the frame detecting section 55 are arranged on the transmission path side, but the present invention is not limited to such a configuration.
For example, the compression unit 51, the bit removal unit 44, the decoding unit 48.
(52) and the bit addition unit 46 causes the frame synchronization signal F
If it is transparent to 0, F1, F2, etc., the frame addition unit 54 is set to the frame detection unit 53.
And the frame detector 55 may be directly arranged in series with or integrated with the frame addition unit 47, and these arrangement points may be arranged on the transmission line side and the exchange side. It may be any of

In each of the above-described embodiments, the bit rate of the compression coding transmission system applied to each relay section is 8 kb.
There are two types, ps and 16 kbps, but the present invention is not limited to such a bit rate. For example, the bit rate is 4
A compression coding transmission system of kbps may be applied, and it is also applicable to a combination of compression coding transmission systems of three or more bit rates (compression ratios).

Furthermore, in each of the above-mentioned embodiments, the timer 5 is used.
The compression encoding and the compression decoding are started in the transmission device directly connected to the exchange in which the source and the destination are accommodated based on the lapse of time measured by 6, but the present invention has such a configuration. However, the same timing may be obtained by, for example, a line signal based on a call processing procedure performed by these exchanges.

[0054]

As described above, according to the first aspect of the present invention, the subscribers that oppose each other through a plurality of relay sections to which different compression coding transmission systems are applied accommodate the subscribers. In each of the relay sections, the encoding and decoding are performed only at one end of the nearest relay section, and the difference in bit rate between the relay sections sandwiched between the other ends of these relay sections is simply absorbed. By doing
The transmission line is surely provided.

Therefore, the deterioration of the transmission quality is greatly reduced as compared with the conventional example in which such compression encoding and compression decoding are repeatedly performed for each relay section. In the invention described in claim 2, different compression encoding is applied to the relay section connected to the incoming route of the exchange containing the callee and the relay section connected to the outgoing route of the exchange containing the caller. Due to the fact that the transmission method is applied or a transmission device other than the transmission device according to the present invention is arranged at any of the relay points forming the transmission path sandwiched between these relay sections, the subsequent relay The fact that the relay cannot be performed by only adjusting the bit rate for the section is sequentially and reliably transmitted to the transmission device at the relay point preceding the relay section.

Therefore, for the existing transmission network in which the combination of the compression coding transmission method applied to each relay section and the transmission apparatus according to the present invention are not arranged, the encoding and decoding are performed for each relay section. By doing so, relay transmission is surely performed. According to the invention described in claim 3, the transmission device according to the present invention is arranged on the outgoing route or incoming route of the exchange that accommodates the caller and the callee, and the identification information is not given from the exchange. However, the difference in the format of the call signal between the ingress route and the egress route and the inter-station transmission line directly connected to them is due to the compression coding and the compression decoding that realize the conversion of the format. Is reliably absorbed by.

That is, in a network to which these inventions are applied, while flexibly adapting to a combination of compression coding methods individually applied to each relay section, it is possible to provide a service with high accuracy and better transmission quality than the conventional example. Offer is realized. Furthermore, existing transmission equipment can be effectively used while adapting to the technology related to the compression-encoding transmission method that is significantly progressing.
It is possible to flexibly construct a corporate network and other branch line networks while suppressing an increase in costs.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the invention described in claims 1 to 3. FIG.

FIG. 2 is a diagram showing the configuration and operation of an embodiment corresponding to the invention described in claims 1 and 3.

FIG. 3 is a diagram showing a configuration of transmission devices arranged at both ends of the first and third relay sections.

FIG. 4 is a diagram showing a configuration of transmission devices arranged at both ends of a second relay section.

FIG. 5 is a diagram showing a format of a signal transmitted / received for each relay section.

FIG. 6 is a diagram showing the configuration and operation of an embodiment corresponding to the invention described in claims 2 and 3.

FIG. 7 is a diagram showing a configuration example of a conventional transmission device.

FIG. 8 is a diagram illustrating an operation of a conventional transmission device.

[Explanation of symbols]

 11 Code Decoding Means 13 Bit Rate Adjusting Means 15 Compressed Transmission System Notifying Means 17 Relay Mode Discriminating Means 21 Relay Mode Notifying Means 31, 34, 91, 93 Exchanges 32, 94 Transmission Equipment 33, 92 Relay Exchanges 41, 53, 55 Frames Detection unit 42, 45, 81, 83 Switch 43, 51 Compression unit 44 Bit removal unit 46 Bit addition unit 47, 54, Frame addition unit 48, 52 Decoding unit 56 Timer 82 Compression encoding unit 84 Compression decoding unit 85 Codec

Claims (3)

[Claims] 1. A binary command to be input is specified by being arranged between an incoming route and an outgoing route of an exchange and an inter-station transmission line to which a compression coding transmission system having a different bit rate is applied. A code decoding means for absorbing the difference in the format of the call signal between the two when taking the logical value of, and the command takes a logical value different from the specific logical value. Bit rate adjusting means for inserting or developing dummy bits in a call signal transmitted and received between the ingress path or the egress path and the inter-station transmission path, and absorbing a bit rate difference, A call which is given in advance identification information indicating a compression coding transmission method applied to an inter-channel transmission line and is transmitted from the encoding / decoding means and the bit rate adjusting means to the ingress path or the egress path. A compression transmission method notifying means for adding the identification information to the signal, and the compression encoding transmission method identification information capable of absorbing the bit rate difference by the bit rate adjusting means are given in advance. Relay mode discriminating means for discriminating the difference between the identification information added to the call signal given from the entry route or the outgoing route and the presence or absence of the lack of the identification information, and outputting the result of the discrimination as the command. A transmission device comprising: 2. The transmission device according to claim 1, wherein the command output from the relay mode discrimination means is added to the call signal sent from the bit rate adjusting means toward the inter-station transmission line, A relay mode notifying means for sending out to a transmission path, wherein the bit rate adjusting means, in addition to the call signal received via the inter-station transmission path,
A call transmitted from the bit rate adjusting means to the inbound route or the outbound route includes means for transmitting the command added to the call signal to the compression transmission method notification means. A transmission device, characterized in that it includes means for adding a command transmitted by the bit rate adjusting / adjusting means to the signal together with or instead of the identification information given in advance. 3. The transmission device according to claim 1 or 2, wherein the relay mode determination means measures a length of a period in which identification information is not added to the call signal, and the length of the period is input. When a threshold value set in advance to a value equal to or greater than the reciprocal number of the minimum response speed of the exchanges facing each other through the route or the outgoing route is exceeded, the identification information of the different discrimination targets is considered to be different. Transmission equipment.