DE1917043A1 - Scanning device for a large number of scanning points - Google Patents

Description

STANDARD ELECTRICAL LORENZ "« - ■ "" ", -

7 Stuttgart-i

Eallmuth-Hirth-Str. 42

J. Hofbauer - 1

Scanning device for a large number of scanning points

The invention relates to a scanning device for a plurality of scanning points which assume two switching states can, e.g. from subscriber lines of a centrally controlled telephone exchange, in which the sampling points cyclically queried for the switching status and the scanning result with the scanning result. of the previous scanning be compared and in the case of only a change in the scanning result compared to the previous one Scanning result a control process is triggered. Such an operation of a scanning device is called a so-called "last-look method" has become known.

^ telephone exchanges with such a scanning device are e.g. from the article "A High-Speed Line Scanner for Use in an Electronic Switching System" by A. Heiner and L. Gröller, published in the Bell System Technical Journal, November 1958, or from the German Auslegeschrifts 1 158 125, 1 137 085 and 1 284 470 known.

December 27, 1968

Vo / lg o / o

'^; ■■ - ■■ - ■ 009842/0656

In the known arrangements, the memory elements that during scanning, the status of the scanned scanning point up to the next scanning and the one to be carried out Record comparison, arranged centrally. This has the advantage that these storage elements can be combined with other storage elements, E.g. for an identifier allocator of the central control part arranged and summarized and available there Writing and reading devices can also be used. The scanning of the scanning points, e.g. the subscriber lines, takes place decentralized. Each scanning result is transmitted to the central control, where the Comparison with the stored scanning result of the previous one Scanning is performed. If the scanning results do not match, the central control immediately the known switching processes triggered. In these known arrangements, the comparison device is only used once required per telephone exchange. However, there must be an exchange of information with each scanning step of the scanning device take place between the scanning device and the central controller. This is particularly disadvantageous if the scanning device is accommodated in a sub-office and the central control is carried out via the main office. As the title of the cited publication already shows, the known arrangements require a very high sampling frequency can be selected in order to record all changes quickly enough for all sampling points in time-multiple operation «

In order to record relatively short dialing characters, a pail proposed to increase the sampling frequency for dial signal reception raise. This requires a considerable amount of switching means. The demands on the operating speed of the comparison device and the central control are very high, see above that considerable effort is required for the implementation.

009842/0656

J. Hofbauer -

The file is the scanning result obtained during the comparison in the Usually very monotonous and indicates that no change has occurred. The speed of operation of the comparator is not only determined by the duration of the switching states of the .. 'sampling points, but also by the fact that their occurrence is unsynchronized and yet by sampling should be recorded in a fixed cycle

The scanning device according to German Auslegeschrift 1 284-470 now reduces the redundant flow of information from the scanning device to the central control and thus also the required scanning speed. The sampling points becomes a separate memory matrix next to the sensor matrix assigned. The scanning result of the previous scanning is stored in the memory matrix. The comparison finds in the scanning device itself and only if the scanning results change, an identity is established via the The scanning point and the changes made are transmitted to the central control system. This reduction in the flow of information is particularly advantageous if the scanning and the comparison are carried out in a sub-office and only those for the changes derived information can be transmitted to the central control of the main office. The effort in the scanning device increases considerably due to its own memory matrix.

It is the object of the invention, in a scanning device for a large number of scanning points, which according to the "last-look method" works to significantly reduce the cost of storage and comparison means compared to the known arrangement. The scanning device for a large number of scanning points which can assume two switching states, e.g. from Subscriber connection lines of a centrally controlled Perneprech exchange system, in which the scanning points are cyclically queried for the switching state and the scanning result with compared to the scan result of the previous scan and only if there is a change in the scanning result compared to the previous scanning result

009842/0656

J. Hofbauer " .

Control process is triggered, is characterized according to the invention, that the scanning result of a group of Sampling points forms a code word from which a testτ generator an assigned test information is derived, that only this test information for the groups of sampling points recorded and compared with the test information of the 'previous sampling cycle and that with, -> Mismatch of test information with the assigned, test information held in the previous scan cycle a control operation is carried out. With such a Design of a scanning device only need the test information from the various groups of scanning points. be cached and compared. This requires a ™ considerable reduction in storage resources ·

According to a further embodiment of the invention, the sampling points are combined into a sampling matrix, the number of columns by the number of sampling points per group and whose number of lines is determined by the number of groups of sampling points. In the case of cyclic scanning the scanning points are queried line by line.

According to a particularly simple embodiment, the comparison and storage of the test information is facilitated by the fact that the two switching states of a sampling point are defined by the logic symbols "O" and "1" logical symbols "1" is checked and that with an even number a check bit ¹¹ O "and with an odd number a check bit" 1 "is generated as check information. more than one change of state in the cycle duration only occurs with a negligible probability.This condition is easy to switch on if the sampling points are grouped

009842/0656

J. Hofbauer -

be queried. For the storage of this simple test information, only one memory flip-flop is assigned to each group of scanning points, ie to each row of the scanning matrix. These memory flip-flops are controlled in such a way that, when scanning, the test information generated by the test generator and the test information stored in the associated memory flip-flop are compared with one another and that, if they do not match, the test information generated by the test generator is saved in the memory. Plip-flop is taken. To initiate the switching processes to the central control, it is provided that the scanning matrix is assigned a scanning counter and memory and that if the test information does not match, the position of the scanning counter and the scanning result of the scanned group of scanning points are transferred to the memory of the scanning matrix during the comparison. I ¹ Ur the Pail that if the test information does not match, the changed code word and the counter setting cannot be stored in the memory of the scanning matrix, a marking flip-flop is assigned to each group of scanning points in addition to the memory flip-plop, which is used in Change of the memory flip-flop is set when the memory of the scanning matrix is occupied. The acceptance of the changed code word and the counter setting can then also be carried out in a subsequent scan if the test information matches. The set marker flip-flop indicates that the information has yet to be transferred to the memories of the scanning matrix. After the information has been deposited, the larkier-Plip-Plop is reset.

The invention is illustrated by means of one in the drawing Telephone concentrator field office explained in more detail.

The subscriber stations TIn of the concentrator external station can be connected in a known manner via a switching network Ki ¹ to the concentrator lines KI leading to the main office. the

0Q9842 / 0GS6. ./.

J. Hofbauer - 6

The marker E takes over the setting of the coupling network KP with the buffer memory PSP, which is transmitted via the data receiver DB the data line DI2 with the central control: the main office and get their setting information from there. About this connection establishment and the call handling In this context it only needs to be stated that the connection sets! K-VS with the transmission devices DS2 of the data line DI2 are coupled.

For the present invention, it only depends on the subscriber lines The focus is to feel the outward parts and only when there are changes the changed conditions via the data transmitter DSl and the data line DU to the main " to transfer office.

The subscriber lines are closed in a known manner. summarized in a scanning matrix TSM. The 512 subscriber lines of a concentrator branch office can, for example, be divided into 52 groups. 16 participants each. These lines Subscriber Loop _v groups are scanned. The control and the selection of the lines of the scanning matrix TSM is carried out by a scanning counter Z. The switching states "0" and "1% ie" line open "and" line closed ", of the 16 scanned subscriber lines form a code word with 16 digits., A check bit is assigned to this code word by the check generator P (J- in a known manner. For this purpose, it is determined: whether the number of switching states "1" in the code word is an even or an odd number. Accordingly, the check bit takes the value "Q" or " 1 1 ". modified until the next sampling of the switching state of a Teilnehmeranschlusslextung this group, then the number of Schaltzuatände changed""in the code word, and accordingly the check bit. it is already the" to derive a condition for the sample. in one scanning cycle More than one change of switching state may only occur in a group with a negligible probability, if one considers the changes in the switching state, the part clearly record subscriber connection lines wsill «

009842/0656

J. Hofbauer -

The check bit obtained when the group was scanned is shown in held in a memory flip-flop YFF so that the following scanning of this group via the comparison circuit VS a comparison of the test bit just received from the test generator PG and the check bits held in the memory flip-flop VFF of the previous scan can be carried out. If these check bits match, the sampling continued without providing any information. If these check bits do not match, the one received from the check generator PG Check bit entered in the memory flip-flop VFF. Via the comparison circuit VS and the control circuit S with the clock generator TG for the sampling counter Z is the position of the sampling counter Z and the sampling result of the subscriber lines of the group just queried are transferred to the memories X-Sp and Y-Sp. Above these two pieces of information is the Identity of the subscriber lines and their switching status fixed. This information is transmitted in a known manner via the control circuit S and the data transmitter DS1 of the data line DLI transferred to the main office. This transfer of information can be carried out independently of the scanning cycle.

If a mismatch is found when comparing the check bits and the memories X-Sp and Y-Sp are currently occupied, then the memory flip-flop VFF assigned to the group being scanned is set to the test bit generated by the test generator PG. At the same time, the marking flip-flop ISFF assigned to the memory flip-flop VFF is set. This marking flip-flop MFF indicates that the information assigned to this group has yet to be transmitted. In a following Sampling and free storage X-Sp and Y-Sp will be the counter position and the relevant one even if the check bits match .Code word entered in the memories X-Sp and Y-Sp. With this transfer, the marking flip-flop becomes MFF again deferred. The information stored in the memories X-Sp and Y-Sp is sent out again under the Control of the control circuit S via the data transmitter DS1 and. the data line DLL

009842/085 6 ./.

J. Hofbauer -

As this exemplary embodiment shows, there are 512 subscriber connection lines only .32 memory flip-flops and marker flip-flops MFF to carry out the scanning after the "last-look-procedure" is required. Since at a scanning a & rode 16 subscriber lines are always queried, results a sufficiently short scan cycle to take this simplified test information the changes of state safely capture.

The size of the group and the assignment of test information according to other aspects, according to the invention, any can be varied. This only affects the design of the test generator PG and the storage means for holding and comparison of this different type of test information.

9 claims

1 sheet of drawing, 1 fig.

009842 / D8E6

Claims (1)

Patent claims Scanning device for a large number of scanning points that can assume two switching states, e.g. from subscriber lines of a centrally controlled communication switching system, in which the scanning points are queried cyclically according to the switching state and the scanning result is compared with the scanning result of the previous scanning and in which only when the The scanning result is triggered compared to the previous scanning result (so-called last-look method), characterized in that the scanning result of a group (e.g. 16) of scanning points forms an Öodeword, from which assigned test information is derived via a test generator (PG), that only this test information for the groups of sampling points is recorded and compared with the test information of the previous sampling cycle and that if a test information does not match with the assigned test information from the previous sampling cycle, it is recorded In the test information, a control process is carried out U .-- ■ -, ---- ^ - ^ ■ ^ -, - ^ - ^ '^' ^^ - ■ rcj:; ^^. Scanning device according to Claim 1, characterized in that the scanning points are combined to form a scanning matrix (TSM) are whose number of gpalteyes; by d4 &: .. points of a "group and the number of lines of which are determined by the number of groups of sampling points. 5. Scanning device according to claim 1 and 2, characterized in that that the lines of the scanning matrix (TSM) are scanned / grounded cyclically. 4 · Scanning device according to claims 1 to 3, characterized in that the two switching states of a scanning point are determined by the logic symbols ¹¹ O "and" 1 ", so that in the case of a scanning result of a group of scanning points via the December 27, 1963 Vo / lg 009842 / Π656 ./ < OfJiGfNAt INSPECTED J. Hof tauer ^1V , Check generator (PG-) the number of logical symbols "1" is checked and that with an even number a check bit "0" and with an odd number a check bit "1" as check information is generated "(parity check). 5. Scanning device according to claim 4, characterized in that each group of scanning points, i.e. row of the scanning matrix, a memory flip-plop (VPP) for this test information assigned. 6. Scanning device according to claim 1 to 5, characterized in that that during a scan the test information generated by the test generator (PG) and the in the assigned memory plug-in w Plop (VPP) recorded test information are compared with one another and that if they do not match, the test information generated by the test generator (PG) is transferred to the memory Plop-Plop (VPP). 7. Scanning device according to claim 1 to 6, characterized in that that the_scanning matrix -4 £ SJ £). a • ■ ^ t ^^ S ^ hleSr-Xz ^^ u ^^ E "" -'- ■ "- ^; ^^ ³ '-" ~ -Sp ^: e ± eni§r ~ fX-Spi ^ Y-SpX "are assigned and that if the test information does not match during the comparison, the position of the sampling counter (Z) and the. Scanning result of the scanned group vori ^ _4btas. ^ Bunkten, .._ i ^ .. Äi ^^ eiQh.eir, 4fe§gf.r '- "" ** " Y-SpJ""of the ~ AWäs-taiatrix are adopted. 8. Scanning device according to claim 1 to 7, characterized in that that each group of sampling points is assigned a marking-flip-plop (MPP) in addition to the storage plip-plop (VPP) is that when the memory plip-plop (VPP) changes is set when the memories (X-Sp, Y-Sp) of the scanning matrix (TSM) are occupied, i.e. the changed scanning result not yet able to take over. 009842/0656 ORIGINAL INSPECTED J. Hofbauer - ^f Scanning device according to Claim 8, characterized in that even if the test information and the set Marking flip-flop (MPF) the free memory (X-Sp, Y-Sp) of the scanning matrix (TSM) the position of the scanning counter (Z) and take over the scanning result of the scanned group of scanning points and the marking flip-flop (MFF) is postponed. 0098 42/0656 omomAL INSPECTED Blank page