JPH0448835A - Signal format converter - Google Patents

Abstract

PURPOSE:To use a conventional digital relay line trunk without any modification by providing a synchronization bit insertion circuit and a frame synchronization shift circuit, and converting a user network side signal format into a standard signal format of an exchange side. CONSTITUTION:Since a same signal format is employed for a 0-th bit string and a 2nd bit string at a private branch. exchange 21 and a 1st class communication enterprise network 24, they are sent to a multiplexer circuit 1 as they are. '0' is inserted to a 1st bit string once per 8 frames at a digital relay trunk 22 and the result is sent to the multiplexer circuit 1. A frame synchronization bit of each bit string is detected in 3rd bit string-7th bit string by frame synchronization circuits 8-12 and a bit position is shifted so that the said synchronization bit is located to a 1st frame bit in a signal format by shift circuits 3-7. Thus, the signal format of the 1st class communication enterprise network is converted into a standard signal format of the private branch exchange.

Description

[Detailed Description of the Invention] [Summary] Regarding a signal format conversion device that converts a signal format when connecting an exchange and a user network via a digital trunk trunk, the conventional A signal format conversion method that converts the signal format on the user network side to the standard signal format on the exchange side when connecting the user network to the exchange via the digital trunk trunk. The apparatus includes a synchronization bit insertion circuit that inserts a frame synchronization bit into the bit of the first frame of the first bit string of the user network side signal format, and each of the third to seventh bit strings of the user network side signal format. It comprises a frame synchronization/shift circuit that performs frame synchronization on the bit string and shifts the bit position to the bit position of the standard signal format on the exchange side.

[Field of Industrial Application] The present invention relates to a signal format conversion device that converts signal formats when connecting an exchange and a user network via a digital trunk trunk.

[Prior Art] Conventionally, as shown in FIG. 6, in order to connect a digital trunk line from the user network 25 to the private branch exchange 21,
Dedicated digital trunk trunk 2 on the private branch exchange 21 side
2 are provided and connected via this digital trunk trunk 22.

[Problems to be Solved by the Invention] When the user network is a unique digital communication network such as a first-class telecommunications carrier network, there is a difference in the frame format of the signaling system between the local exchange side and the user network side. arise.

That is, the signal format on the private branch exchange side is the standard signal format of the TTC (Telegraph and Telephone Technical Committee) as shown in Figure 4, while the signal format of the Type 1 carrier network is as shown in Figure 5. It's like being able to do something.

In Figure 4, the signals handled within the private branch exchange are
The first to eighth frames each consist of one signal time slot TSO and 30 speech time slots TSI.
- Consists of TS31. The signal time slot TSO further consists of eight hits, and the signal format is constituted by each signal time slot TSO of the first to eighth frames.

In this signal format, the first frame bit (horizontal bit array in Figure 4) of the first bit string (vertical bit array in Figure 4) is a frame synchronization bit.
is inserted. This frame synchronization bit V is "0", so the bit at this position becomes "0" once every eight frames. Also, *1 bit is inserted into each frame bit of the second bit string. This *1 bit is "0" when it is normal and 'l' when it is abnormal.Furthermore, the *2 bit is set to the first frame bit of the third to seventh bit strings, and the *2 bit is set to "0" when it is normal and 'l' when it is abnormal. Channel bits CHI to CH30 are inserted into the bits, and *3 bits are inserted into the 8th frame bit. *2 bits alternately change to O/l every multiframe when normal, and *3 bits are normal. When there is no call, it becomes "1" and when there is an abnormality, it becomes "0". Each channel bit CHI-CH30 becomes "°1" when there is no call, and becomes "O" when there is a call. Furthermore, a fixed value "1" is inserted into the second to eighth frame bits of the O-th bit string and the first bit string.

In Figure 5, the signal format of the Type 1 Ministry of Communications Network is such that the O-th bit string and the first bit string are all fixed values.
1", and the second bit string is the *l bit. The third bit string to the seventh bit string constitute handling groups HGI to HG5, respectively. In each handling group) (Gl to HG5, the first to *2 bit and *3 bit are inserted in either position of the 8th frame bit. Here, *2 bit is used as a frame synchronization bit, and normally changes to 0/I every multiframe. However, when there is an abnormality, the value will be other than this. Also, *3 bits will be °°1" when normal and °0 when abnormal, and each channel bit CHI to CH30 will be "1" when there is no call,
It becomes °0°゛ when talking.

Ru.

As a result of the difference in signal format between the exchange side and the user network side, it is not possible to connect the exchange to the user network 24 such as a class 1 carrier network using the gauge digital trunk trunk 22 as is. Ta.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a signal format conversion device that performs signal format conversion so that conventional digital trunk trunks can be used as they are when connecting an exchange and a user network.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In order to achieve the above object, the present invention provides, as one form, a signal that converts a signal format on the user network side into a standard signal format on the exchange side when connecting the user network to the exchange via a digital trunk trunk. The format conversion device includes a synchronization bit insertion circuit 101 that inserts a frame synchronization bit into the bit of the first frame of the first bit string of the user network side signal format, and a synchronization bit insertion circuit 101 that inserts a frame synchronization bit into the bit of the first frame of the first bit string of the user network side signal format, and the third to seventh bit strings of the user network side signal format. A frame synchronization/shift circuit 102 that performs frame synchronization for each bit string up to and shifts the bit position to the bit position of the standard signal format on the exchange side.
The product is provided with the following:

Another aspect of the present invention is a signal format conversion device that converts a standard signal format on the exchange side to a signal format on the user network side when connecting the user network to the exchange via a digital trunk trunk, the device comprising: l insertion circuit 1 that inserts '1' into the bit of the first frame of the first bit string of the standard signal format on the exchange side
03 is provided.

[Operation] For a signal from the user network side to the exchange, the synchronization bit insertion circuit 101 inserts a frame synchronization bit into the first bit string of the signal format, and the frame synchronization/shift circuit 102 inserts a frame synchronization bit into the third bit string to Re-format the 7th bit string. As a result, the signal format on the user network side is converted to the standard signal format on the exchange side.

Also, for signals from the exchange side to the user network,
The inserting circuit 103 inserts '1-' into the first frame bit of the first bit string of the signal format. As a result, the standard signal format on the exchange side is converted to the signal format on the user network side.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram illustrating the connection arrangement position of the signal format conversion device according to the present invention. In the figure, 21 is a private branch exchange, 22 is a digital trunk trunk, 23 is a signal format conversion device, and 24 is a first type communication carrier network as a user network. The signal format conversion device 23 is arranged between the digital trunk trunk 22 and the first type carrier network 24.

A schematic configuration of an embodiment of this signal format conversion device is shown in FIG. In FIG. 3, a signal from the first type communication carrier network is separated into a speech channel and a signal channel, and the speech channel is inputted to the multiplex circuit 1. The signal channel consists of the Oth bit string and the second bit string in the signal format shown in Figure 5.
The bit string is directly guided to the multiplex circuit 1, the first bit string is guided to the multiplex circuit 1 via the 0 insertion circuit 2 which inserts "0" into the first frame bit, and the third to seventh bit strings are guided to the multiplex circuit 1. Each column has frame synchronization circuits 8 to 1.
2 and shift circuits 3 to 7 to multiplex circuit 1.

In addition, the signal from the private branch exchange 21 side passes through the 1 insertion circuit 13 that inserts "1" into the first frame bit (that is, the position of the frame synchronization bit V) of the first bit string of the signal format shown in Fig. The data is sent to the network side.

The operation of this embodiment device will be explained below. First, conversion of the signal format from the first type communication carrier network 24 to the private branch exchange 21 will be explained.

A digital signal input from the first type communication carrier network 24 is divided into a speech channel and a signal channel, and the signal channel is further divided into 0th to 7th bit strings. As shown in FIGS. 4 and 5, the O-th bit string and the second bit string
Since the signal format is the same on both sides, it is sent to the multiplex circuit 1 as is.

The first bit string does not have a frame synchronization bit in the type 1 carrier network signal format, but on the digital trunk trunk 22 side, a frame synchronization bit V is required as shown in FIG. By passing through the insertion circuit 2, "O" (that is, frame synchronization bit v) is inserted once every eight frames and sent to the multiplex circuit l.

Regarding the third to seventh bit strings, frame synchronization circuits 8 to 12 first detect frame synchronization bits*2 (see Figure 5) for each bit string, and then shift circuits 3 to 7 detect the above-mentioned detected bits. Frame synchronization bit*
The bit position is shifted so that 2 is in the position of the first frame bit in the signal format and then sent to the multiplexing circuit 1. As a result, the signal format of the type of carrier network shown in FIG. 5 is converted to the standard signal format of the private branch exchange shown in FIG. 4.

The multiplex circuit 1 multiplexes the speech channel and the signal channel and sends it to the digital trunk trunk 23.

Next, conversion of the signal format from the private branch exchange 21 to the first type communication carrier network 24 will be explained.

The difference between the standard signal format of the 21 examples of private branch exchanges and the signal format of the 24 examples of type 1 carrier networks is that the first bit string of the first bit string of the signal format on the private branch exchange 21 side
The frame bit (frame synchronization bit = 0) is "1" in the signal format on the first type communication carrier network 24 side. The format of the third to seventh bit strings of the signal format of the first type communication carrier network 24 is corrupted, but the first type communication carrier network 24
Therefore, even if the format of this part is as shown in FIG. 4, there will be no problem in operation. The same applies to the digital trunk trunk 22.

Therefore, only the first bit string of the signal channel from the exchange 21 side is guided to the 1 insertion circuit 13, where "1" is inserted into the first frame bit (position of frame synchronization bit V). That is, once every 8 frames. ``1'' is inserted at a rate of 1 and sent to the first type communication carrier network 24.

Private branch exchange 21 (i.e. digital central line trunk 2
The other bit strings of the signal from 2) to the first type communication carrier network 24 do not need to be sent with their formats broken, so they are sent to the first type communication carrier network 24 as they are.

[Advantageous Effects of the Invention 1] As explained above, according to the present invention, conventional digital trunk trunks can be used as they are when connecting exchanges and user networks, and therefore assets can be used effectively. In addition, since the signal format conversion device is configured to be compatible with digital trunk trunks,
It has a redundant configuration that is resistant to failures and can separate processing loads.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is a diagram showing the connection arrangement of a signal format converting device according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a signal format converting device according to an embodiment of the present invention. , Figure 4 is a diagram showing the standard signal format on the private branch exchange side, Figure 5 is a diagram showing the signal format on the Type 1 carrier network side, and Figure 6 is a diagram showing the conventional network connection configuration. be. In the figure, ■...Multiple circuit 2...0 insertion circuits 3-7...shift circuits 8-12...frame synchronization circuit 13...1 insertion circuit 21...private branch exchange 22... Digital trunk line trunk 23...Signal format conversion device 24...Explanatory diagram of the principle related to the first class telecommunications carrier Amimoto Komei Figure 1 - Signal border of the Pingtong rental business network - Muft mat No. 5 figure

Claims (1)

[Scope of Claims] 1. A signal format conversion device that converts a user network side signal format into an exchange side standard signal format when connecting a user network to an exchange via a digital trunk trunk, the device comprising: A synchronization bit insertion circuit (101) inserts a frame synchronization bit into the bit of the first frame of the first bit string of the format, and a synchronization bit insertion circuit (101) performs frame synchronization for each bit string from the third bit string to the seventh bit string of the user network side signal format. A signal format conversion device comprising a frame synchronization/shift circuit (102) for shifting the bit position of the bit position to the bit position of the standard signal format on the exchange side. 2. A signal format conversion device that converts a standard signal format on the exchange side to a signal format on the user network side when connecting a user network to an exchange via a digital trunk trunk, the device converting a standard signal format on the exchange side into a signal format on the user network side. A signal format conversion device comprising a 1 insertion circuit (103) that inserts "1" into the bit of the first frame of a bit string. 3. A signal format conversion device comprising the signal format conversion device according to claim 1 and the signal format conversion device according to claim 2.