DE19608114A1 - Communication switchgear - Google Patents

Description

The invention relates to a communication switchgear according to the Ober Concept of claim 1, in particular to a private switching system (private Automatic Branch Exchange = PABX).

When operating a PABX, a subscriber dials a number of digits, which of the PABX can be interpreted, which then creates a call connection to an or outside line, which by at least one of the digits dialed is identified. If the subscriber has one or more area codes, for example if 9 dials, the PABX connects the line of the calling subscriber with an outside line and the 9 following digits leads a central office to which the outside line is connected to an outside call connection to manufacture.

The numbering plan, as used for example in North America, be contains a convention, which confuses between area key figures and Central office numbers avoided. Central office numbers are limited in that that the middle of the first three digits is between 2 and 9 inclusive, while the middle digit of area codes is either 0 or 1.

These restrictions no longer exist. Area codes and outside codes are now interchangeable.

In addition, every telephone company has had local service in the past Performance monopoly and the numbers dialed were by the central office establishment of this telephone company detected. Telephone connections were made (in some legislative areas) either through the local telephone company provided or the company for the telephone connections was from the local phone company selected. This monopoly has been broken and that local subscribers can now select the company they want for telephone connections choose yourself.  

This creates a difficulty for PABX systems because they are capable must distinguish between digits that are dialed within the PABX the digits that determine a called subscriber, who via a local Central office can be reached and digits indicating the connection with another Produce service providers without area codes and other Num with the help of the second digits of the number dialed could become as it was possible in the past. However, it is necessary to be able to make this distinction automatically in order to realize savings can be made possible by appropriate selection of different service providers are.

For example, to reach Central Office 416 in the local area, the owner of a PABX would have to program an automatic route selection subsystem within the PABX so that it interprets the number 9416 + 4 subsequent digits (the number 9 denotes a call to the PABX to the outside) so that this call is fed to the local central office and the number 9416 + 7 subsequent digits are interpreted so that the call is forwarded to another service provider. It is generally not possible to do this on ordinary PABX systems because the prefix 9 automatically routes the call to the local central office.

There is therefore the task of a communication switchgear and a procedure provide for their operation, which allows participants access to get inner and outer lines, which by area codes and Zen tralamtscodes are defined that do not correspond to the known standard, where access to other service providers should be possible at the same time.

This object is achieved with the characterizing features of claims 1 or 4. Advantageous refinements can be found in the respective subclaims bar.

According to a preferred embodiment of the present invention, the  PABX can be programmed with the same leading and dialed digits, each but with different digits to follow (dtf) and follows here with different communication channels to create the call connection. The Different ways are followed by the different numbers of successors Numbers determined. In this way, the owner of the PABX can do different things to program call connections for different lengths of the total phone number, measured by the number of digits made up of the part be selected without expressly all the digit combinations of the automati need to define the route selection subsystem.

Some embodiments of the invention are described below with reference described in more detail in the accompanying drawings, which show:

FIGS. 1A and 1B are block diagrams of a communication system for live implementation of the present invention,

Fig. 2 represents a table munikationswege be selected based on the dialed digits Kom,

Fig. 3, 3A and 3B are diagrams of an embodiment of the present OF INVENTION dung and variations of this embodiment,

Fig. 4 is a diagram of another embodiment of the invention,

Fig. 5 is a diagram of another embodiment of the invention,

Fig. 6 is a block diagram of the structure of an embodiment of the invention, and

Fig. 7 is an illustrative diagram of the operation of the invention.

In Fig. 1A is a typical PABX 1 is shown, to which a telephone set 3 is connected. The PABX is connected via trunk lines 7 to a central office and via trunk lines 11 to equipment 9 from another provider.

The central office 5 is connected to a telephone set 13 , also with trunk lines LD for long-distance calls, which lead to other offices. The third-party equipment 9 is also connected to remote third-party equipment via its own telephone lines CLD.

In the drawing it is shown that the subscriber can dial the number 416 + 4 subsequent digits after the initial digit 9, i.e. a total of eight digits or seven digits, which follow the digit 9 for leaving the PABX, and the PABX must make the call connect to the Central Office 5 . The subscriber can also dial 9416 + 7 digits, that is a total of eleven digits or ten digits following the number 9 and the PABX must connect the call to the equipment 9 of the other provider. The subscriber can also dial 9 976 555 + 4 subsequent digits, for a total of eleven digits or ten digits subsequent to the initial digit 9, and the PABX must connect the call to the local central office. The subscriber can also dial 9 976 976 + 4 subsequent digits, for a total of eleven digits or ten digits following the initial digit 9, and the PABX must connect the call to the local central office.

Fig. 2 illustrates this example in a table. The first column contains the selected after the initial number 9 digits, the second column contains the number of the following paragraphs, the third column contains the type of the path and the fourth column contains the different path numbers, which the PABX must follow in order to establish the call connection.

Fig. 1B is a block diagram of a communication switching system in the manner of egg ner PABX, in which the present invention is implemented. The base system is sold by Mitel Corporation under the designation SX2000 and is described, for example, in U.S. Patents 4,615,028 issued September 30, 1986 and 4,616,360 issued October 7, 1986, both of which are owned by Mitel Corporation. Reference is hereby made to these patent specifications. To avoid repetition, no detailed description of these systems is given below because their structure is known to the person skilled in the art. However, it should be noted that the system is controlled by a central processor 17 , which produces call connections to and from and between trunk lines and internal lines 19 or 21 A and 21 B via correspondingly numbered interfaces.

The lines 21 A represent lines to a central office, for example to the central office 5 from FIG. 1, and the lines 21 B represent lines to another provider 9 according to FIG. 1.

The PABX 15 has a tree of digits in a RAM 23 which, together with the processor 17 , is used to decode the communication path of a call according to the digits received from the line. In the past, led decoding a code number 9 to the processor instructing the system to supply the remaining digits via a line 21 A a central office.

According to the present invention, a memory 25 is provided which has a specialized database for use as an adjunct for the number tree, as will be described below. The memory is referred to as the database 25 and is connected to a bus 27 of the system 15 for access by the processor 17 .

Fig. 3 schematically shows the numeric tree 29 within the RAM memory 23. The area above the dotted line corresponds to the state of the art. The digit tree is a database with pointers 31 from identified received numbers in a line or the lower branch of the tree to higher branches which carry digits corresponding to digits chosen later. For example, a first digit 9 is found in a lower branch D0 and has a pointer to a branch Da. The number 4, which is chosen next in the sequence 416, is found in the branch Da and has a pointer to the branch Db. The next selected digit 1 is in branch Db and has a pointer to branch Dc. The next selected number 6 is located in the two Dc and has a pointer to the communication path R1, the identity of which is immediately below the reference number 6 . The known system therefore only allows the assignment of a single communication path to the selected digits 9416.

According to an embodiment of the present invention, the database 25 (shown below the dotted line) consists of a numerical index element I, which has a pointer to a further branch Dd of the tree. The initial branch Dc of the number tree, which contains the path R1 corresponding to the received number 6, now leads back the communication path R1 if only four numbers follow the selected number 6; however, if there are seven subsequent digits, the index to branch Dd is used and returns the communication path R2.

The index data item in branch Dc (which extends into database 25 ) may point to branch Dd or contain no reference, in which case there is no pointer to another branch. It can also point to branch Dd and the element of number 6 of branch Dd can also disappear.

The branch Dd (and higher branches) can have their own index I, which may point to a higher branch, or may have a vanishing entrance have what indicates that higher branches need not be accessed, then what the case is when there are no further digits received (digits from the Participants were chosen for analysis by the central unit), and no number of the following digits is larger than indicated in branch Dd.

Branch Dd may have representations of more than one set of initial digits, as shown in FIG. 3A. The same applies to branch Dd. 9415 may have more inputs assigned to this number than 9416, as shown in FIG. 3B. The input under Dd or the input under nothing can be "nothing".

The path which corresponds to the received digit in the highest branch with a zero index denotes the communication path which the processor uses instead of the path in the original digit tree in RAM 23 to set up the call connection. The chosen route can lead to one of a variety of long distance or local call providers, a central office, etc.

It can thus be seen that the chosen route depends on the number of digits selected far, with the branch in the expanded tree from one index to one Extension of the database depends. It should be noted that the extension too depends on the numerical element. For example, the extension of the Number of digits of branch Dc may be smaller than the number of subsequent digits of the branch Dd.

If the digit element in branch Dc is zero, the system assumes that the smallest Number of subsequent digits (4) is received and route R1 is selected. If the digit index element in branch Dc points to branch Dd, this takes System that the next largest number of subsequent digits (7) is received and route R2 is selected. If the index number in branch Dd becomes a shows another branch, e.g. B. to De (not shown) is assumed that a other number of subsequent digits follows, e.g. B. 10, and another way, e.g. B. a Route R3 can be used to set up the call connection. The De branch can have an index input of zero or another pointer to another Branch that identifies another expected number of subsequent digits.

It should also be noted that each of the branches of the same connector as Dc is one has the same structure. For example, instead of 9416 as a result show in branch Dc 9976 to branch Dc ′ (not shown), which is an index number for additional numbers of subsequent digits as described above.

It should also be noted that the use of index numbers no longer results in a simple tree structure, since once a certain number of successive digits has been exceeded, a pointer to a branch of the tree exists, which both identifies a number of subsequent digits (via a branch , which results from a specific received digit) as well as a specific communication path, which is to be used by the processor to set up the call connection. Each subsequent digit that goes beyond the expected number calls another index, which leads to another higher number of expected subsequent digits and thus to a different communication path, and not only to a branch, which depends on the actual number received , as is the case with the number tree 29 .

The index used can be the actual number of subsequent digits, as shown in the exemplary embodiment according to FIG. 4. In this case, the subsequent digits are determined by system 15 , which receives the dialed digits and counts the decoded digits using processor 17 , or a specialized digit receiver which both decodes and counts the digits received. The number of digits is determined by the processor, which defines a time interval after each digit and determines the establishment of the call connection after a predetermined interval has elapsed. A digit to limit the time or to end the dialing process can be provided, which indicates the last digit in the received sequence of digits.

With the number of subsequent digits after the initial digits which are known in the branch Dc of the digit tree, this known number of digits can be used as an index for a database 25 , on which the pointer moves from the digit 6 in the branch Dc to the branch VBa will be shown. In this embodiment of the database 25 , the subsequent digits are sorted in ascending order, assigned to path identifiers. For example, if the number of digits following the initial digits 9416 is 7, the path R2 is identified and returned to the processor 17 to identify the communication path used to establish the call connection. The route is selected using index 7 , and the corresponding route R2 is immediately identified instead of waiting for further digits received and going through the tree at higher levels, as shown in the embodiment of FIG. 3. If the following digits result in zero, there is no input 9416 + 0.

A further embodiment is shown in FIG. 5, wherein instead of the index of the number 6 in branch Dc, which points to branch VBa, a superblock consisting of branches SBa is indicated. The superblock is composed of an array of records, which is zero to TO digits long and deep due to the number of subsequent digits (25 are shown) (TO denotes "time-out", that is, the passage of time). The subsequent digits form the index in the superblock and the path is saved when the last digit is cut in the initial digit sequence and the value of the subsequent digits.

Fig. 6 shows a structure which can be used to implement the embodiments described above. The processor communicates with a data entry system 33 which generates a table 35 on a display 37 . The table allows entry by the operator of the PABX, a route selection list. For example, for the leading digit 9, the operator enters a list of dialed digits (e.g. 416) and subsequent digits (e.g. 4, 7), with a correlation to routes (route 1 , route 2 , etc.).

The processor translates the data from table 35 to database 25 , which has a table 39. Table 39 contains the groups of leading and dialed digits, e.g. 9416, 9613, etc. Each group has its own sub-group, which is a termination list that assigns the following digits (dtf) ways, e.g. B. dtf 4 to route 1 , dtf 7 to route 2 for 9416; dtf 5 to route 3 for 9613 etc. Within each sub-group the dtf values are sorted by increasing size.

Fig. 7 shows the operation of this structure. A receiver 43 receives the dialed digits and the processor 17 translates the received digits (shown as a functional translation block 45 ). For example, the receipt of the digits 9416-xxxx (where xxxx can denote any dialed digits) means that the translator 45 points to the input 9416 of table 39. The translator 45 counts the number of subsequent digits (4 of xxxx), which is used as an index for the entry into the subgroup 41 , which outputs the route 1 . This data is fed to the processor 17 , which processes the call using the communication path 1 .

It should be noted that the database may be included in RAM 23 along with other data or on a hard drive or other storage device in PABX 15 ( FIG. 1B).

Claims (5)

1. Communication switchgear with

• (a) a device for receiving dialed digits relating to a call,
• (b) a memory for storing a table of groups of initial digits and for storing a sub-table for each group of initial digits, each sub-table consisting of a list of the number of digits to be expected to follow a corresponding group of initial digits and each number with a communication path is correlated, each list of the number of digits being sorted in ascending order,
• (c) a device for selecting a group of initial digits in the table corresponding to the first selected digits and for indicating a communication path corresponding to the smallest number of digits in a sub-table of the selected group of initial digits,
• (d) a device for using this communication path to set up the call connection if the dialed digits have a number of digits which corresponds to the smallest number of digits,
• (e) a detection device for detecting an additional digit selected according to the number of digits and for indicating the next largest number of digits in the sub-table of the selected group of initial digits, and
• (f) a device for repeating step (e) until no more dialed digit is detected, which exceeds the highest number of digits to which reference is made and a corresponding communication path in the sub-table is used to set up the call connection.

2. Communication switchgear according to claim 1, characterized by a Device for detecting the values of the received dialed digits, for Determine whether an initial group of digits was chosen, which corresponds to a group of initial digits in the table for counting the number of digits that follow the initial group of dialed digits and to generate a digits-to-follow (dtf) signal and to select the Communication path via an index which corresponds to the value of the dtf signal within the subtable that corresponds to the values of the initial digits corresponds. 3. Communication switchgear according to one of the preceding claims, there characterized in that the number of tables of a preselected Group list corresponds to initial digits and a device for ver call processing is performed using all dialed digits without the number of digits dialed from the initial group the numbers are counted and without a communication path from a table to select if the initial group of digits is not a saved one Group of initial digits. 4. A method for operating a communication switchgear according to one of the preceding claims, characterized by the following method steps

• (a) Receive dialed digits relating to a call
• (b) storing a table of groups of initial digits and for each group of initial digits a sub-table, each sub-table consisting of a list of numbers of expected digits which follow a corresponding group of initial digits and each number correlated with a communication path and each list sorted by numbers of digits in ascending order,
• (c) selecting a group of initial digits in the table corresponding to the first digits selected and indications of a communication path corresponding to the least number of digits in a sub-table of a selective group of initial digits,
• (d) using this communication path to establish the call connection if the dialed digits contain a number of digits which corresponds to the least number of digits,
• (e) detecting a dialed number beyond the number and indicating the next largest number of digits in the sub-table of the selected group of initial digits,
• (f) repeating step (e) until no more dialed digits are detected which exceed a maximum number of indicated digits and using a corresponding communication path which is contained in the sub-table for establishing the call connection.

5. The method according to claim 4, characterized in that the values of received dialed digits are detected, it is determined whether a initial group of digits was selected, which is one of a group digits in the table corresponds to counting a number of digits the initial group of dialed digits and generating a digit-to follow (dtf) signal and the selection of the communication path by a Index which corresponds to the value of the dtf signal within the sub-table, which corresponds to the values of the initial digits.