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PER FURU Subscriber Equipment Division Telefonaktiebolaget LM Ericsson Fig. 2 Block diagram for the stored program controlled PABX, ASB100 rotary dial and push-button telephone instruments. The use of push-button telephone sets, which in addition to the ten digit buttons have buttons with the star and square symbols, makes it possible to provide such facilities as - individual abbreviated dialling - automatic call diversion - bypassing of automatic call diversion - direct switching to a loudspeaking telephone. The push-button telephone sets also have another button, the register button, for calling in a register, for example when making an inquiry call. Special importance has been attached to the utilization of the possibilities offered by a stored program controlled system as regards operation and maintenance and also administration. As regards operation and maintenance the aim has been to reduce the need for qualified staff and training to a minimum. This has been achieved through a well designed functional system structure in combination with advanced test programs and easily understood documentation. The administration of the system has been made more efficient and flexible since certain tasks can now be allocated to the operator, and because it is possible to arrange central administration of several PABXs via the public telephone network. System design ASB 100 can be divided into a switching equipment and a control system. The exchange of information between these two takes place via a bus system. Fig. 2 shows a block diagram of the system. The units shown in unbroken lines constitute the standard equipment in the exchange and the units shown in broken lines are supplementary equipments, which can be supplied if required. Switching equipment ASB 100 is equipped with an electronic switching network that is built up of thyristor crosspoints. This means that redirection in the switching network can be carried out very quickly and that the network can be used not only for speech communication but also for the connection of different signalling units. Such units include the tone sender, which gives different types of tone information to the extension, or the dialling tone receiver, for receiving the dialling tone from the public network when this occurs. The use of a single-stage thyristor crosspoint switching network makes it possible to order the setting up of different connections direct from the units concerned, for example extension line circuit and tone sender, when initiating a call. Thus special circuits for setting up the switching network are not required.
13 When the receiver is lifted the extension is connected to a tone sender that sends the dialling tone, after which dialling can start. If a conventional telephone set with a dial is used, the dialled digits are received direct in the extension line circuit, but if a telephone set equipped for tone frequency key sending is used, the digits are received by a push-button dialling tone receiver, which is connected to the tone sender. In both cases the digit information is transferred via the bus system to the control system for further analysis. If the digit analysis indicates that the call is internal, a connection is set up via a free local junctor trunk to the desired extension. If the call is external, a free line is connected up to a dialling tone receiver. Thus the extension is now connected to a tone sender and a trunk line to a dialling tone receiver. The external number can now be dialled and registered in the same way as in the case of an internal call. When the public exchange works with decadic impulsing the external number is transmitted with the aid of circuits in the trunk line circuit regardless of whether the extension has a telephone set with a dial or a push-button telephone set. The dialling tone receiver is disconnected when the dialling tone has been received. In cases where there is a second dialling tone the receiver remains connected until this tone has been received. The extension is connected to the external line when the dialling tone ceases. The tone sender is disconnected when the transmission of digits is completed. When an external call comes in, the trunk line is connected to the operator's console, after which the operator can dial the desired extension number and set up the call. A characteristic feature of ASB 100 is that the operator works with only one operator link. It is used only when the operator is actively engaged in any part of the call handling. Other functions, which concern the operator's work indirectly, such as ringing, camp on busy, parking etc., affect only the units concerned, for example external and extension lines, and are controlled completely from the central control system. Control system The control system in ASB 100 is built up around processor APN 163, developed by LM Ericsson, which is a powerful, general purpose 16-bit processor that is designed for a number of applications in different fields of activity. The choice of memories was based on a desire to obtain high flexibility at a low cost. For this reason permanent mem- Fig. 3 Operator's set
Page 1: ERICSSON REVIEW 1 1978 OPERATIONAL
Page 5 and 6: ERICSSON REVIEW NUMBER 1 • 1978
Page 7 and 8: 3 STEN RIMBLEUS Stockholm Telecommu
Page 9 and 10: Fig. 4 (left) The operation and mai
Page 11 and 12: Types of faults, measures and subsc
Page 13 and 14: 9 ABDULLAH AL-SABEJ Chief Engineer
Page 15: Stored Program Controlled PABX, ASB
Page 19 and 20: 15 five such matrices permit connec
Page 21 and 22: 17 Fig. 8 Printed board assembly fo
Page 23 and 24: Technical data Capacity Number of e
Page 25 and 26: 21 HENNING ANDERSEN VILLYK. PEDERSE
Page 27 and 28: 23 signalling was to be carried out
Page 29 and 30: 25 Fig. 10 Simplified block diagram
Page 31 and 32: Fig. 12 The principle for common tr
Page 33 and 34: PER-ALRIK HALLBERG THORWALD LUNDMAR
Page 35 and 36: 31 Fig. 9 Regulation range for the
Page 37 and 38: Fig. 12 Power feeding of the line r
Page 39 and 40: 35 oscillators also cease operating
Page 41 and 42: Technical data Electrical data Cabl
Page 43 and 44: 39 CHRISTOPHER LORENZ Financial Tim
Page 45 and 46: The Ericsson Group With associated

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