The Ericsson Group 1968 - History of Ericsson - History of Ericsson
The Ericsson Group 1968 - History of Ericsson - History of Ericsson
The Ericsson Group 1968 - History of Ericsson - History of Ericsson
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Equipments for Maintenance<br />
<strong>of</strong> ARF 102 Automatic Telephone Exchanges<br />
V. ERIKSSON, TELEFONAKTIEBOLAGET LM ERICSSON. STOCKHOLM<br />
30<br />
UDC 621.395.722.7<br />
LME 1548<br />
<strong>Ericsson</strong> Review No. 2, 1966, under the heading "Centralization Trends in<br />
Exchange Maintenance", contains an account <strong>of</strong> the maintenance philosophy<br />
recommended by L M <strong>Ericsson</strong> and <strong>of</strong> how maintenance work can be rationalized<br />
through centralization. 1<br />
<strong>The</strong> present article contains a brief account <strong>of</strong> standard equipments used for<br />
maintenance <strong>of</strong> ARF 102 exchanges and <strong>of</strong> equipments for centralized service<br />
supervision <strong>of</strong> a multi-exchange area. <strong>The</strong> choice <strong>of</strong> equipment will depend on<br />
the size <strong>of</strong> the exchange and on the network structure. An exchange in a<br />
single-exchange area will not have the same equipment as exchanges in a<br />
multi-exchange area with centralized supervision. Suitable equipment for sonic<br />
typical cases is listed in a table at the end <strong>of</strong> the article.<br />
Owing to the high requirements placed at the design stage on the reliability<br />
<strong>of</strong> circuitry and components, L M <strong>Ericsson</strong>'s crossbar switching systems are<br />
very reliable in operation. <strong>The</strong>re are therefore good prospects <strong>of</strong> maintaining<br />
these types <strong>of</strong> equipment for a very low labour effort. This is confirmed by<br />
many administrations.-<br />
But even if faults seldom occur, it is important that disturbances which<br />
affect subscribers should be immediately indicated and that means should<br />
exist for tracing the faults. To fulfil this requirement with a minimum <strong>of</strong><br />
manual labour, equipment is required which automatically supervises the<br />
functional quality, primarily from the subscriber's point <strong>of</strong> view, and provides<br />
indications when the quality is unsatisfactory. This equipment is supplemented<br />
by supervisory circuits, built into common control devices, which indicate<br />
disturbances in the function <strong>of</strong> these devices. 3<br />
Maintenance Equipments<br />
A prerequisite for the maintenance philosophy recommended by L M <strong>Ericsson</strong><br />
is the use <strong>of</strong> maintenance equipments which are so reliable that all doubt<br />
concerning their objectivity can be excluded.<br />
<strong>The</strong>y may be divided into six groups for the following purposes:<br />
• supervision<br />
• indication<br />
• fault tracing and testing <strong>of</strong> switching equipment<br />
• repair <strong>of</strong> faults<br />
• fault tracing and testing <strong>of</strong> subscriber lines<br />
• traffic measurements.