JPH10224826A - Path connecting resistance reducing method for mdf system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the accumulated resistance value of a path to be not more than a value fixed by a standard by setting the algorithm of path selection so as to avoid selecting an even-numbered matrix board concerning all the three stage of switch parts at the time of constituting a path through the three stages of switch parts using a set matrix board. SOLUTION: In a set MB consisting of two matrix boards(MB), as even- numbered MB is away from a connector than odd-numbered MB, a maximum resistance value is as large as 4.6ohm. At the time of setting a path, a priority second MB kind selection means 1c identifies the kind of even-numbered or odd-numbered MB at first and third switches from a housing table 2a and sets the kind of MB at a second switch by referring to a discrimination table 2b, which preferentially designates odd-numbered MB concerning the second switch when even-numbered MB is assigned with the first and second switches, e.g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing a path connection resistance for reducing a DC resistance in an MDF (Main Distribution Frame or Main Distribution Frame) system.

[0002] The DC resistance of an MDF system is mainly given by the sum of the conductor resistances of a matrix board (MB) and a back-wired board (BWB) in the system. Generally, in the MDF, the physical specifications such as the size of the matrix board (MB) and the wiring specifications are optimized according to the system scale. In addition, in order to accommodate a greater number of subscriber lines, the area of the MDF has increased, and its conductor resistance has increased in proportion to it. May not be possible.

[0003]

2. Description of the Related Art FIG. 7 is a diagram for explaining the functions of an MDF (main distribution board or line distributor) system. The MDF is a device for connecting each subscriber line to which a plurality of subscriber terminals (telephones or the like) are connected to a designated subscriber circuit of the exchange, and is often provided in the exchange. May be accommodated in a subscriber terminal installed outdoors.

[0004] When a large number of subscriber lines are collected in a station building as a cable bundle underground or above the ground, each line is connected to an arrester via a connector. The arrester has a function to protect the exchange against overcurrent (lightning strike, short circuit, etc.). Each subscriber line is connected to the MDF via an arrester. The configuration of the MDF is shown in FIG. The other end is connected to each subscriber circuit of the exchange via a connector via the MDF path, and a part is connected to a transmission device in which a trunk line is accommodated.

[0005] The MDF connects a new line to a subscriber circuit of an exchange when a new subscriber joins, or changes the connection when the subscriber moves or changes a telephone number. Or to change the connection of the path to the subscriber's circuit of the exchange in order for the subscriber to receive a new service (for example, from a subscriber circuit for normal telephone service to a subscriber circuit for ISDN service). Provide functions. M
The change of the connection of the DF path may be performed while the exchange is operating. To efficiently change the path connection, the number of terminals on the subscriber side (for example, 360
0 terminals) are provided more than the number of terminals on the exchange side (for example, 2100 terminals).

In the conventional MDF, a terminal board for accommodating a subscriber line is provided, and a pair (each constituting a subscriber line) is provided between the subscriber line and the terminal board and between the terminal board and the subscriber circuit of the exchange. The connection between the subscriber and the exchange is made by manually connecting the two terminal boards with jumper wires. Therefore, this work requires a specialized technician, and requires a lot of time since the work requires detailed manual work. Therefore, in recent years, an automatic MDF in which a robot performs a jumper operation has been introduced.

FIG. 8 shows a configuration example of a conventional MDF. A.
As shown in FIG. 1, the MDF is composed of three stages of a primary switch (SW), a secondary switch (SW), and a tertiary switch (SW). And a plurality of matrix boards (referred to as MB) as shown in FIG. In order to connect between the subscriber line and the exchange (subscriber circuit), a connection path passing through each switch unit is formed. MB is a multilayer printed board, and is printed and wired so that many lines in the X (row) direction and many lines in the Y (column) direction intersect at right angles in different layers. A. In the example, the line in the row direction is wired on the front surface, and the line in the column direction is wired on the back surface indicated by the dotted line. Each row and column wiring is connected to a terminal of a connector provided corresponding to a wiring in each direction provided on one side of the matrix board by a printed wiring.

At each intersection of a plurality of wirings in the row direction and the column direction of the MB, a difference hole (hole) is provided, and a connection pin (not shown) is inserted into the difference hole from above to obtain a desired hole. The lines in the row direction and the lines in the column direction can be electrically connected (paths are connected). In recent years, insertion of connection pins has been automatically performed by robots.
Each subscriber line is composed of a pair of A line and B line.
By inserting a connection pin into each difference point, the difference points of a pair of lines A and B are connected. The above A. 3 shown
In order to connect the subscriber line and the subscriber's circuit of the exchange at the switch unit of the stage, one connection pin is inserted at each difference point of each matrix board constituting the primary, secondary and tertiary switch units. There is a need. After the connection is made by inserting the connection pins, the connection is maintained semi-fixed unless the subscriber moves or the subscriber circuit is changed.

The number of wirings in the row direction and the number of wirings in the column direction of each matrix board are restricted by the physical size of the matrix board, the density of wiring patterns, and the like, and a fixed number of wirings are accommodated (for example, , Row direction / column direction is 2
00 pairs x 120 pairs).

FIG. 9 is a diagram for explaining the relationship between the respective switches.
FIG. Indicates the connection relationship between the matrix boards in each switch section. Each of the primary to tertiary switch units is composed of a large number of matrix boards (MB), and is provided with a tertiary switch connected to a subscriber circuit from an arbitrary input terminal of the primary switch unit in which a subscriber line is accommodated. A configuration is provided such that an arbitrary terminal is connected to a path. That is, in FIG. As shown in (1), each matrix board of the primary switch is provided with printed wiring so that it can be connected to all matrix boards of the secondary switch section, and this wiring is called a link.
Similarly, each matrix board of every secondary switch is provided with a link for connecting to every matrix board of the tertiary switch section.

FIG. Indicates a physical configuration for accommodating the matrix board. The matrix board is a plug-in type Back Wired Board (BWB)
And is connected to each terminal of a back wired board (BWB) by a connector. On the back wired board (BWB), A.B. The printed wiring patterns forming the links as shown in FIG. That is, 1
Links are provided so that the matrix boards of the next to tertiary switch units can be connected to each other.

[0012] The MDF system having such a configuration is employed in a public network telephone office. One of the electrical standards is a loop resistance of an A / B line (A / B line resistance from the primary switch to the tertiary switch). The target is that the line resistance when the line and the B line are folded at the end is 10 Ω or less, and it is specified that the line resistance is 20 Ω or less in operation.

On the other hand, as a new matrix board (MB), a set matrix board (set MB) on which a plurality of MBs are mounted is adopted, and FIG. 10 shows a configuration of a set MB on which two MBs are mounted.

In FIG. 10, reference numeral 10 denotes a set MB, 11,
Reference numeral 12 denotes a matrix board (M
B), respectively. In this example, there are 124 difference points in the row direction and 100 difference points in the column direction.
Difference points are provided. Among the MBs 11 and 12, the MB 11 provided at a position farther from the connectors (15 and 16) described later (the DC resistance value of the path to the connector is high) is set to an even number (or an old number). An odd number (or called a young number) is set for the MB 12 close to the connectors 15 and 16 (the DC resistance value of the path to the connector is low).

Reference numerals 13 and 14 denote connection pin supply units for supplying connection pins when the connection pins are automatically inserted into the difference points. Each of the MBs 11 and 12 is initialized (when the connection pins are not used).
, Each having a capacity to supply 120 pins.

Reference numeral 15 denotes a connector of 440 pins (two pins A and B, each for one line and for 220 lines), which are connected to respective lines of the matrix boards 11 and 12 in the Y-axis (vertical) direction. Wiring is formed on the surface of the board, and each connector of the connector 15 is connected to each line on the back wired board by inserting the set MB10 at a predetermined position of the back wired board (see B in FIG. 9).
When this set MB is used as a primary switch section, an external subscriber line is connected to this connector 15, and when it is used for a tertiary switch section, it is connected to a subscriber circuit of an external exchange. Called.

Reference numeral 16 denotes a connector of 496 pins (for 248 lines), which is a row (horizontal) of the matrix boards 11 and 12.
The printed wiring connected to each line in the direction is formed on the back surface (or an intermediate layer) of the board, and this connector 16 connects each pin to each line on the back wired board by inserting the set MB10 into the connection position of the back wired board. Is done. When this set MB10 is used as a primary to tertiary switch section, this connector 16 is called a link connector because it is connected to a link.

This set MB10 corresponds to A.1 in FIG. 1 shown
Each of the primary to tertiary switch units constitutes a matrix board of any one of the primary to tertiary switch units, and has a set MB of a number designed corresponding to the scale of the exchange (the number of subscribers accommodated). It is provided as.

When a switch section is constituted by using a plurality of sets MB, an even number (or an old number) is set for the matrix board 11 provided at a position distant from the connectors 15 and 16, and the connectors 15 and 16 are assigned to the connectors 15 and 16. An odd number (or called a young number) is set for the near matrix board 12. For example, when a certain switch unit is composed of a plurality of set MBs, No. 0 and No. 1 are set to two matrix boards of the first set MB, and No. 2 and No. 3 are set to two matrix boards of the next set MB. Are set, and the numbers are set sequentially in the same manner. In the case of the above even-numbered (older) matrix board 11, the matrix board 1
The path through 1 to the connector 16 has a long resistance and therefore a high resistance value, and the path through the odd-numbered (youngest) matrix board 12 has a short distance and a low resistance value.

In an MDF system using two matrix boards 11 and 12 of a set MB10 shown in FIG.
The horizontal size is 538.9 mm and the vertical size is 2
32 mm. This size, compared to the conventional MB,
The area ratio is 6 times, and the conductor resistance has increased several times.
The maximum resistance value per MB (path passing through even-numbered matrix boards) is 4.6Ω (loop), and the path passing through odd-numbered matrix boards has a lower resistance value.

On the other hand, in order to maintain communication quality, the maximum value of the resistance value in the MDF is specified by a public telecommunications carrier, and the total resistance value in each of the primary to tertiary switch units is defined as: The sum of the resistance of the link between the primary switch and the secondary switch (formed by a back-wired board) and the resistance of the link between the secondary and the tertiary switch may be less than 20Ω. Has been requested.

FIG. 11 is a diagram showing the M when a set MB equipped with two MBs is connected to a back-wired board (BWB).
It is explanatory drawing of the connection route of DF. In the figure, 10a to 10c
Is a set M of each of the primary to tertiary switch units.
B, which are primary MB, secondary MB, and tertiary M, respectively.
Represented as B, 17 represents BWB. 1st MB to 3rd M
B is an even-numbered (older) MB 11a, 11b,
11c and odd numbered (younger) MBs 12a, 12b, 12c
And IO connectors 15a, 15b,
A link 15b and link connectors 16a, 16b, 16c are provided, and a link is formed by connecting to the BWB 17 and connected to the line side (subscriber line) and the inside of the office (subscriber circuit of the exchange).

In the case of FIG. 11, the subscriber line is connected from the BWB 17 to the IO connector 15a of the primary MB 10a, and is connected to the link connector 16a through one difference point (not shown) of the even-numbered or odd-numbered MB. It is connected to the link of BWB17. This link is then connected from the link connector 16b of the secondary MB 10b to the IO connector 15b via one of the difference points of the even (old) MB 11b or the odd (young) 12b, and is connected to the link of the BWB 17. . The link is further connected from the BWB 17 to the link connector 16c of the tertiary MB 10c.
It is connected to the IO connector 15c via the difference point of 1c or 12c and is connected to the inside of the station. The paths of the MDF are thus connected.

[0024]

The MD shown in FIG.
In F, the paths are connected by arbitrarily selecting the matrix boards constituting the primary, secondary, and tertiary switch sections, but the two matrix boards mounted on each aggregate matrix board are all switched in each switch section. If it is an even number (older number), the type resistance of the matrix board is 13.8Ω (4.6
(Ω / MB × 3 oldest MB) and the worst conductor resistance of the BWB (when the link wiring pattern is the longest) is 8Ω, so that there is a problem that the standard of 20Ω cannot be satisfied in total.

FIG. 12 shows the distribution of the total resistance value when the primary to tertiary switch units include path connections via all even-numbered (older) MBs. The actual value of the distribution of the value obtained by adding the resistance values of the third to third switch units. The vertical axis is the number of paths, and the horizontal axis is the total resistance value of each of the three switch units (excluding the resistance value of the back wired board). ).

According to the present invention, there is provided an MD for connecting a subscriber line to a circuit of an exchange by using a collective matrix board on which a plurality of matrix boards are mounted and passing through a three-stage switch section.
It is an object of the present invention to provide a path resistance reducing method for reducing the cumulative resistance value of a bus to a value less than a value defined in a standard in an F system.

[0027]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a primary, secondary and tertiary switch unit comprising a matrix board including a plurality of matrix boards. When a path passing through one of the (MB) is selected, a path selection algorithm is provided so as not to select an even number (older number) in all three switch units.

FIG. 1 is a diagram illustrating the principle of the present invention. In the figure,
Reference numeral 1 denotes a processing unit for selecting a matrix board (referred to as a secondary MB) of a secondary switch unit of the MDF comprising three stages of primary to tertiary switch units using an aggregate matrix board, and 2 denotes a memory. In the processing unit 1, 1a is the subscriber accommodation 1
Next MB (matrix board) type identification means, 1b is a tertiary MB identification means for accommodating a subscriber circuit, and 1c is a priority 2 for discriminating which type of an even number or an odd number is given priority as a secondary MB.
Next MB type selecting means, 1d: Secondary MB of the selected type
Priority type selection secondary MB extraction means for searching for a path according to the method described above.
This is another type secondary MB extracting means for searching for B.

In the memory 2, a reference numeral 2a designates a type (an even number or an odd number) of an aggregate matrix board of a primary switch unit and a tertiary switch unit in which a subscriber line and a subscriber circuit of an exchange are accommodated, respectively. ) Is stored, 2b is a discrimination table, 2c is a link between each MB in the primary switch and each MB in the secondary switch, and each MB in the secondary switch and each tertiary switch. 6 is a link table storing a state (free or in use) of a link between MBs.

When one of the secondary MBs is selected, the subscriber line to be connected to the path and the accommodation position of the subscriber circuit on the exchange side to which the subscriber is connected (the number of the MB and the connection therein) Position) is given. First, subscriber accommodation primary M
The B type identification means 1a refers to the accommodation table 2a to identify the type (even number (old) or odd number (young)) of the primary MB in which the subscriber line is accommodated, and then identifies the subscriber. Similarly, the accommodation table 2 in the circuit accommodation tertiary MB identification means 1b
The type of the primary MB is identified with reference to a. Subsequently, the priority secondary MB type selecting means 1c refers to the discrimination table 2b based on the types of the identified primary MB and tertiary MB, and
The secondary MB type to be prioritized is determined. Discrimination table 2b
, Information indicating that the type of the secondary MB to be prioritized or any type is acceptable in accordance with the combination of the types of the primary MB and the tertiary MB.

Thus, when both the primary MB and the tertiary MB are even numbers (older numbers), the odd number (younger numbers) are given priority to the secondary MB, and both the primary MB and the tertiary MB are odd numbers. In the case of (younger number), the even number (older number) of the secondary MB is prioritized. The priority type (1) defined in the determination table 2b by the priority secondary MB type selection unit 1c.
If the next MB and the tertiary MB are of the same type, or if any one of the types is selected as the priority type (when the primary MB and the tertiary MB are different types), then the priority type secondary MB extracting means A search for a secondary MB by priority type is started for 1d.
In this search, the link between the primary MB accommodating the subscriber line performing the path connection and the tertiary MB accommodating the subscriber circuit are selected from among a number of secondary MBs corresponding to the priority type. One secondary MB having a free link between the two is searched with reference to the link table 2c. This makes one secondary MB
When is searched, the process ends. If the secondary MB of the priority type is not detected, the secondary MB extracting means 1e is activated and searches for a secondary MB other than the priority type by referring to the link table 2c. Thereby, one secondary MB can be searched.

However, if the primary MB and the tertiary MB are both even-numbered (old) and odd-numbered (young) are selected as the priority type, the odd-numbered priority type secondary MB extracting means 1d determines the odd-numbered number. If the secondary MB extracting means 1e selects an even-numbered (old) secondary MB when the search cannot be performed, three even-numbered secondary MBs are selected. This is acceptable, for example, when it is necessary to provide a path connection to the subscriber in the state.

In this way, the connection path passing through the primary to tertiary switch sections always passes through the odd number (lower number) having the lower resistance value in one MB.

[0034]

FIG. 2 is a flowchart of a process for selecting a route of a secondary MB according to the embodiment. An accommodation position including the number of the primary MB of the subscriber line to be connected to the MDF in advance;
Depending on the accommodation position including the number of the tertiary MB of the subscriber circuit, 1
It is assumed that the type of the next MB and the type of the tertiary MB have been identified.

When the free route extraction process via the secondary MB starts, one of the three processes is executed according to the combination of the types of the primary MB and the tertiary MB. That is,
When both the primary MB and the tertiary MB are even numbers (old numbers), the selection start secondary MB is set to odd numbers (young numbers) (S in FIG. 2).
1). This odd number corresponds to the priority type described in FIG. Next, if one of the primary MB and the tertiary MB is even-numbered and the other is odd-numbered, the secondary MB to be searched may be of any type, but the selection-started secondary MB is replaced by the previous empty route. The number next to the number of the secondary MB selected in the extraction process is set (S2 in FIG. 2). If both the primary MB and the tertiary MB are odd numbers (young numbers), the selection start secondary MB is set to an even number (old numbers) (S3 in FIG. 2).

When the selection start secondary MB is determined by any one of the above S1 to S3, next, the selection start secondary MB is shifted to 1
A route is skipped one by one (one MB is skipped sequentially) (S4 in FIG. 2). In this case, the link between the primary MB accommodating the subscriber line and the secondary MB to be selected, the secondary MB to be selected and the tertiary MB accommodating the subscriber circuit.
It is determined with reference to the link table 22 shown in FIG.
S5), if there is a free route, the secondary MB is extracted.

If there is no free route, it is determined whether the route extraction for the secondary MB has been completed in one cycle (S
6) If not completed, return to S4 and target secondary M
Change the B number to the next skipped number. As a result, in the case of starting with an even number (odd number) in S4 of FIG.
The next target secondary MB is shifted to the next even-numbered (odd-numbered) secondary MB, and the same empty route is determined for the secondary MB.

When the route extraction has been completed for all the secondary MBs belonging to the type (even number or odd number) of the selection start secondary MB, the root extraction is performed one after the start secondary MB one by one. 2 S7). That is, when the starting secondary MB is an even number (odd number), in S7, a root extraction is performed with the next odd number (even number) secondary MB following the secondary MB as the starting secondary MB, and an empty route is extracted. It is determined whether there is (S8 in FIG. 2). If there is a free route, the secondary MB is extracted. If there is no free MB, it is determined whether the route extraction has been performed twice (S9 in FIG. 2). If not, the process returns to S7, and a similar empty route is extracted for the secondary MB with the next skipped number. If the route extraction has been performed twice, a route busy output is generated and the process ends.

When a secondary MB of the MDF is selected, a secondary MB allocation algorithm (referred to as a secondary MB selection allotter) for uniformly using each MB has been used. This is because the difference points of the secondary MBs are arranged at a high density, and the current secondary point is set to avoid placing a large number of connection pins (inserting into the difference points) in a part of the secondary MBs. It has a function of selecting a candidate for the position (number) of the secondary MB suitable for the next use based on the use state of the MB.

The present invention can be implemented by using the processing flow of FIG. 2 when a candidate for a secondary MB is selected by the conventional algorithm for selecting a secondary MB. Will be explained.

FIGS. 3 and 4 are explanatory diagrams (part 1) and (part 2) of specific examples showing the order of secondary MB selection. Figures 3 and 4
, 10-1, 10-2,..., 10-n represent a plurality of sets MB constituting the secondary switch unit. In this example, n sets MB are provided. In each set MB, 11 is an even-numbered (older) secondary MB, 12 is an odd-numbered (younger) secondary MB, and the uppermost set MB10-1
Nos. 0 and 1 (represented by # 0 and # 1) are assigned to the secondary MBs 11 and 12 of the set MB 10-1 and 10
As shown in FIGS. 3 and 4, for each of the secondary MBs 11 and 12 of −2,..., Numbers 2, 3, 4, 5, 6, 7,.
Numbers 2 (n-1) and 2n-1 are set.

FIG. 3 shows a case where the secondary MB selection allota selects the secondary MB of # 3 (odd number, young number) and the odd number (young number) is selected as the priority type in the processing flow of FIG. The following shows an outline of the sequential processing of (not shown).

First, the secondary MB selection position by the secondary MB selection allotter is # 3, and if the younger (odd) is determined as the priority type in step S1 of FIG. 2, both points are odd. Selection start position # 3
The root extraction is started with the secondary MB of # 3 as the secondary MB of #.

If the root is not extracted for the secondary MB of # 3, the same processing is performed for the secondary MB of # 5, skipping one next. Hereinafter, all the odd-numbered secondary M until the route is extracted
Extraction is performed for B, and when the extraction is completed, the process ends.

If extraction of all odd-numbered (youngest) secondary MBs of # 3, # 5, # (2n-1) and # 1 fails,
Even number 2 next to the above first selection start position (# 3)
Extraction starts from the next MB (# 4).

If the extraction fails with the secondary MB of # 4, all the even-numbered secondary MBs (# 6, # 8,..., # 0, # 2)
Is extracted until the extraction is successful, and if the extraction is successful, the extraction processing ends.

If the extraction fails in # 2, the extraction process is terminated and a route busy is output. FIG. 4 shows a selection process when the secondary MB selection allotter selects the secondary MB of # 0 (even number, old number) and the odd number (young number) is selected as the priority type in the processing flow of FIG. Indicates the order of
(Not shown) will be outlined below.

First, the secondary MB selection position by the secondary MB selection allota is # 0, and step S1 in FIG.
If the odd number (young number) is determined as the priority type by (or S2), the two do not match in terms of the odd number and the even number. , And # 1 is set as the selection start position. The root extraction is started with the secondary MB of # 1.

If the root is not extracted for the secondary MB of # 1, the same processing is performed for the secondary MB of # 3, which is skipped by one next. Hereinafter, all the odd-numbered secondary M until the route is extracted
Extraction is performed for B, and when the extraction is completed, the process ends.

If extraction of all odd-numbered (lower-numbered) secondary MBs of # 1, # 3,... # (2n-1) fails, the even number next to the first selection start position (# 1) Secondary MB of the number
Extraction is started from (# 2).

If the extraction fails with the secondary MB of # 2, the root extraction is performed until all the even-numbered secondary MBs (# 4, # 6,..., # 0) succeed. To end.

If the extraction fails in # 0, the extraction process is terminated, and the root business is output. Although FIGS. 3 and 4 described the case where the priority type is an odd number, the case where the priority type is an even number (in the case of step S3 in FIG. 2) is based on the same principle as the secondary MB selection order. Is performed.

In step S2 of the processing flow of the route selection in FIG. 2, if the primary is the old number and the tertiary is the young number or the primary is the young number and the tertiary is the old number, "selection start 2" Next M
B is set next to the previous selection. However, when the secondary MB selection allota selects the secondary MB position (number), the selected secondary MB position (number) is even or odd. , The route extraction process can be started from that position.

FIG. 5 shows the distribution of the total resistance value of the MB when the third even number (old number) is avoided according to the present invention. This corresponds to FIG. 12 described above. In the path passing through the matrix board of each of the primary to tertiary switch units, the third even number M
The distribution of the cumulative resistance value is shown for 2,000 paths when the path passing through B is not included, the vertical axis represents the number of paths, and the horizontal axis represents the cumulative resistance value of three matrix boards. As is apparent from comparison with the distribution of the maximum resistance value in the case of including the even number shown in FIG. 12, the path connection resistance can be reduced by about 2.6Ω on average. In the case of FIG. 5, the maximum value is 10.1 Ω, and even if the resistance value of the back wired board (BWB) is added to 8 Ω, it is 18.1 Ω, which can satisfy the standard (20 Ω or less).

In the above description, an example in which two MBs are provided on the collective matrix board has been described.
With respect to the MDF using the collective matrix board including B, the path resistance can be reduced according to the same principle.

FIG. 6 shows an example of an aggregate matrix board on which many MBs are mounted. In this example, a total of 16 MBs # 0 to # 15 are provided in one aggregate matrix board. In this case, # located far from the connector
Boards 0, # 4, # 8 and # 12 are the oldest and the other M
B (# 1 to # 3, # 5 to # 7, # 9 to # 11, # 13 to
# 15) are all the younger players. When such an aggregate matrix board is configured as each of the primary to tertiary switch units of the MDF, the resistance of the path can be reduced by avoiding the connection which becomes old in all three switch units according to the principle of the present invention. Can be reduced.

[0057]

According to the present invention, a three-stage switch unit is used in an MDF in which a subscriber line is connected to a circuit of an exchange by a path through a three-stage switch unit using a collective matrix board on which a plurality of matrix boards are mounted. , It is possible to reduce the resistance value of each connection path through a constant value to a certain value or less. As a result, the signal quality of all the subscriber lines can be changed to MDF.
At a certain level or more.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram illustrating a processing flow of route selection of a secondary MB according to the embodiment;

FIG. 3 is an explanatory diagram (part 1) of a specific example showing a secondary MB selection order;

FIG. 4 is an explanatory diagram (part 2) of a specific example showing a secondary MB selection order.

FIG. 5 is a diagram showing a distribution of the cumulative resistance value of the MB when a 3 even number (old number) is avoided according to the present invention.

FIG. 6 is a diagram illustrating an example of an aggregate matrix board on which many MBs are mounted.

FIG. 7 is an explanatory diagram of functions of the MDF system.

FIG. 8 is a diagram illustrating a configuration example of a conventional MDF.

FIG. 9 is an explanatory diagram of a relationship between switch units.

FIG. 10 is a diagram showing a configuration of an aggregate matrix board on which two MBs are mounted.

FIG. 11 is an explanatory diagram of a connection path of an MDF when a set MB having two MBs is connected to a back-wired board.

FIG. 12 is a diagram illustrating a distribution of cumulative resistance values in a case where each of the first to third-order switch units includes a path connection via an even-numbered (older) MB.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing part 1a Subscriber accommodation primary MB type identification means 1b Subscriber circuit accommodation tertiary MB identification means 1c Priority secondary MB type selection means 1d Priority type secondary MB extraction means 1e Other type secondary MB extraction means 2 Memory 2a Housing table 2b Discrimination table 2c Link table

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoto Kaneko 3-9-118 Shin-Yokohama, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Fujitsu Communication Systems Limited (72) Inventor Masao Hosugai Kami-Odanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 4-1-1 1-1 Fujitsu Limited (72) Inventor Rie Takada 4-1-1 1-1 Kamiodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (3)

[Claims] 1. An MDF system for forming a connection path via a three-stage switch unit for connecting a subscriber line to a subscriber circuit of an exchange, wherein each switch unit includes a plurality of matrix boards mounted thereon. Each matrix board is provided with a plurality of vertical and horizontal lines and a difference hole for inserting a connection pin into each difference point to form a connection path. A connector connected to each line by a wire at an end thereof, and a structure in which the connector is connected to another switch unit and a line by connecting the connector to a back-wired board. The matrix board placed in the primary switch is set as an odd number, and the matrix board placed in a far position is set as an even number, In selecting a connection path via the switch unit, the secondary switch unit, and the tertiary switch unit, at least one of the aggregate matrix boards in the primary switch unit to the tertiary switch is an odd-numbered low-resistance matrix board. A path connection resistance reduction method for an MDF system, comprising selecting a path passing through a path. 2. The matrix board according to claim 1, wherein an odd or even number of a matrix board accommodating a subscriber line to be connected to the collective matrix board of the primary switch unit, and
A matrix board of the primary switch section and the tertiary switch section is identified by identifying an odd-numbered or an even-numbered type of matrix board accommodating a subscriber circuit to be connected to the subscriber line of the collective matrix board of the next switch section. Characterized in that at least one of the three switch units has an odd number as a matrix board type of a set of matrix boards of secondary switch units that connect between the two. Resistance reduction method. 3. The method according to claim 2, wherein one of an odd number and an even number in the set matrix board of the secondary switch section is preferentially selected. Check whether the path between the tertiary switch units is free, and if there is a free space, extract the matrix board. If it is not extracted from any of the matrix boards of the corresponding type, extract the matrix board of another type. A method for reducing the path connection resistance of an MDF system, comprising: