The Ericsson Group 1968 - History of Ericsson - History of Ericsson

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Equipments for Maintenance of ARF 102 Automatic Telephone Exchanges V. ERIKSSON, TELEFONAKTIEBOLAGET LM ERICSSON. STOCKHOLM 30 UDC 621.395.722.7 LME 1548 Ericsson Review No. 2, 1966, under the heading "Centralization Trends in Exchange Maintenance", contains an account of the maintenance philosophy recommended by L M Ericsson and of how maintenance work can be rationalized through centralization. 1 The present article contains a brief account of standard equipments used for maintenance of ARF 102 exchanges and of equipments for centralized service supervision of a multi-exchange area. The choice of equipment will depend on the size of the exchange and on the network structure. An exchange in a single-exchange area will not have the same equipment as exchanges in a multi-exchange area with centralized supervision. Suitable equipment for sonic typical cases is listed in a table at the end of the article. Owing to the high requirements placed at the design stage on the reliability of circuitry and components, L M Ericsson's crossbar switching systems are very reliable in operation. There are therefore good prospects of maintaining these types of equipment for a very low labour effort. This is confirmed by many administrations.- But even if faults seldom occur, it is important that disturbances which affect subscribers should be immediately indicated and that means should exist for tracing the faults. To fulfil this requirement with a minimum of manual labour, equipment is required which automatically supervises the functional quality, primarily from the subscriber's point of view, and provides indications when the quality is unsatisfactory. This equipment is supplemented by supervisory circuits, built into common control devices, which indicate disturbances in the function of these devices. 3 Maintenance Equipments A prerequisite for the maintenance philosophy recommended by L M Ericsson is the use of maintenance equipments which are so reliable that all doubt concerning their objectivity can be excluded. They may be divided into six groups for the following purposes: • supervision • indication • fault tracing and testing of switching equipment • repair of faults • fault tracing and testing of subscriber lines • traffic measurements.
Fig. I Schematic representation of supervisory equipment Super visor v Equipments Fig. 1 shows how different equipments eontinously supervise the function of each part of the switching system of the exchange. For supervision of the entire switching process, i.e. from subscriber to subscriber, use is made of the method of generating traffic with a traffic route tester. TRT, and of the method of supervising real traffic. The two methods supplement one another, and both are used by many telephone administrations. Supervision of real traffic is generally done manually. It is therefore expensive, but on the other hand provides certain information which TRT cannot give. e.g. the subscribers* behaviour. Traffic Route Tester (TRT) The traffic route tester is supplied in two mechanically differing types, one on a detached, special purpose rack and one on a standard BDH rack. 31
Page 1: 2 1969
Page 6 and 7: 32 For each programme a maximum of
Page 8 and 9: 34 Supervision of Common Control Eq
Page 10 and 11: Fig. 4 Supervisory panel for exchan
Page 12 and 13: Fig. 8 Fault tracing «ith manual .
Page 14 and 15: Fig. 12 MFC tester Fig. 13 Electron
Page 16 and 17: Fig. 16 Test set AHP 1622 42 via a
Page 18 and 19: 44 The following tests can be made:
Page 20 and 21: Fig. 20 Transmission of alarm 46 A
Page 22 and 23: 48 Exchanges A—D attended. Mainte
Page 24 and 25: 50 result in wrong connection. With
Page 26 and 27: Fig. 2 Insertion of tone generator
Page 28 and 29: Fig. 4 Exploded view of the push-bu
Page 30 and 31: Fig. 7 Push-button mechanism with l
Page 32 and 33: 58 registered by the V.F. code sign
Page 34 and 35: 60 Description of a Junction Networ
Page 36 and 37: Fig. 4 Kxample of cable runs in a l
Page 38 and 39: 64 Data for Programming The calcula
Page 40 and 41: Interesting New LME Items at "Prote
Page 42 and 43: New Head of Telecommunication Grouo
Page 44: The Ericsson Group Associated and c

The Ericsson Group 1968 - History of Ericsson - History of Ericsson

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