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Development, Production and Maintenance of Software for AKE 13 Lars-Olof Noren and Siwert Sundstrom Transit exchange system AKE 13 and its software have been described in earlier articles in Ericsson Review^- 2 , and also methods and support systems for testing the software 3 . The article gives an insight into the development, market adaptation, production, installation and maintenance of the software. It is important for a modern telephone exchange system that these activities are organized logically and that the system is able to satisfy the various demands made on it. signals, and for making and executing logic decisions, are realized in programs. These are stored in the common control store together with data concerning the build-up of the exchange and network and about the upto-date status of the connection sequences. The structure and function of the programs was described in an earlier article 2 . UDC 621.395.722: 658 581 LME 66 Transit exchange system AKE 13 is a SPC system, fig. 1, that has been developed by LM Ericsson. The basic functions of the systems are already fully developed and in operation, but further development of various functions is going on all the time. The system is adapted to new market requirements by the addition of new basic functions, and above all in the form of the addition of new signalling systems when the system is introduced on new markets. Since the control logic in a SPC exchange is realized mainly in software, new development work consists mainly of software design. Hence LM Ericsson have a staff of software designers both in the parent company and the subsidiary and associated companies. Broadly speaking, the work has been allocated so that the designers in the parent company program various general functions while the subsidiary and associated companies program the functions that are specific for their particular market, for example signalling functions. Support system APT has been developed for the production of software. However, the support functions are not only used for design and the associated testing of new software, but also for all subsequent handling of the software, comprising production of program and data packages for the different AKE exchanges and administrations, and for the maintenance of a comprehensive program library. Software and documentation In a SPC system all functions for storing and interpreting control and state In the following description programs and data are summarized under the concept software. The software must obviously be documentated just as carefully and well organized as the hardware. It has proved to be rational to document and register software products according to the same rules as other articles in the LM Ericsson product range. The basic unit in the system is called a function block or often just block. The block contains program sequences with functionally associated data and hardware units. For example, all program sequences and data records that are used for signalling in a certain type of code receiver, together with the code receiver itself, constitute a code receiver block. Each block is described in a set of documents, which are brought together in a document summary. The medium that is used for a certain document can vary depending on where the document is used. Thus certain documents, forexample program code, are stored on magnetic tape, whereas others are printed and are available in book form, for example operational instructions. Like all other products, during its lifetime the software undergoes a number of changes because of modifications, function additions etc. Each time there is a change of the block program code the block is given a new revision state, which is entered in the document summary, which also includes information regarding which documents have been revised. The document summary thereby unambiguously defines the document set that applies for a certain revision state in the block.
153 LARS-OLOF NOREN SIWERT SUNDSTROM Telephone Exchange Division Telefonaktiebolaget LM Ericsson For a hardware product there are a number of types of documents intended for different user categories. Certain documents are only intended for operation etc. In the same way some of the software documents are intended for inserting the block in a program package for a certain exchange, while other documents are intended for the exchange staff who are to use the function in operation. Thus the software products in the form that they are stored in the program library are not complete exchange functions, but rather production documentation. Analogous with the successful philosophy that LM Ericsson have applied for electro-mechanical crossbar systems, the design of the AKE 13 software has been based on the following requirements'. flexible adaptation to different markets and exchange requirements • successive introduction of functions without radical system changes introduction, without operational disturbances, of function changes and extension to exchanges already in operation • high reliability r^ lowest possible costs for development, planning, production, installation, operation and maintenance • division of the handling of the software between the Ericsson Group's different units and licensees. Fig. 1 Block diagram of the hardware for AKE 13 Fig. 1 a Exchange test position for an AKE exchange Software requirements and program categories These requirements, which in some respects are unique for computer applications, have been possible to fulfil through • a general program system structure with strictly defined interfaces between different function blocks, which enables function blocks to be
Page 1: ERICSSON REVIEW 3 1976 GEOSTATIONAR
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Page 6 and 7: 112 forever silent. The next launch
Page 8 and 9: 114 Figs. 1—4 Figs. 5—8
Page 10 and 11: 116 Figs. 17—20 Figs. 21—24
Page 12 and 13: Electronic Push-button Telephone Se
Page 14 and 15: The bottom part (frame) ot the set
Page 16 and 17: Fig. 10 Buzzer unit Fig. 9 Tone rin
Page 18 and 19: Fig. 12 Impulsing unit and ring uni
Page 20 and 21: 126 Fig. 15 Transmission diagram Fi
Page 22 and 23: 128 ed by about 100 kohms. In order
Page 24 and 25: Fig. 20 DC characteristics (speech
Page 26 and 27: 132 use a microphone in which the o
Page 28 and 29: CCM - A Well- tried and Economic Ma
Page 30 and 31: 136 ] Do not allow more staff in th
Page 32 and 33: Ten Years Experience of CCM in the
Page 34 and 35: 140 Table 2 Existing staff requirem
Page 36 and 37: Optimization of Power Supply Equipm
Page 38 and 39: 144 Initial expenditure. This consi
Page 40 and 41: Table 1 Acquisition costs for diffe
Page 42 and 43: 148 Fig. 8 Instead of feeding the p
Page 44 and 45: 150 Fig. 10 Apart from a highly sta
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Page 50 and 51: 156 duction and putting the package
Page 52 and 53: 158 Fig. 5 Working procedure when p
Page 54 and 55: 160 The error message is sent from
Page 56 and 57: Dr. Christian Jacobceus chaired the
Page 58 and 59: 164 Among the reasons that were giv
Page 60: TELEFONAKTIEBOLAGET LM ERICSSON PRI

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