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Operational Experience from AXE 10 in Sodertalje Sten Rimbleus The Swedish Telecommunications Administration has operational experience of SPC exchanges which goes back to 1968, when the first AKE 12 exchange was put into operation in Tumba near Stockholm. Since then a total of three AKE 13 exchanges have been installed in Stockholm and Gothenburg. The operational experience from these has been good, as has been reported in previous articles in Ericsson Review* ~ 3 . The present article describes the Swedish Telecommunications Administration's field trial and eight months' operational experience from a new generation of SPC exchanges, namely from the first AXE 10 exchange in Sodertalje. The installation has already been described in a previous issue of Ericsson Review 4 . UDC 621.395.722 681.3.065 The Sodertalje exchange Sodertalje is the zone centre for the Sodertalje trunk code area. A number of group centres and terminal exchanges are connected to the exchange. There are direct routes to Stockholm and nearby smaller communities and to a number of other cities in the country, of which Gothenburg and Malmo are the largest, fig. 1. On March 1st, 1977 the new 3000-line AXE 10 exchange in Sodertalje was taken into service. It then took over the corresponding number of lines from the existing AGF exchange, which served approximately 32 000 subscribers. This was the first step in a successive replacement of the AGF exchange (500- line selectors) by AXE 10. The new exchange was put into service with close cooperation between manufacturer and customer, which has to a great extent contributed to a successful result. The Telecommunications Administration's field trial Objectives Before the AXE 10 exchange was put into operation the Administration's staff carried out a 2-week continuous field trial in order to check Fig. 1 Sodertalje trunk code area with some of the larger routes — Route ^ ^ High usage route
3 STEN RIMBLEUS Stockholm Telecommunication Area Swedish Telecommunications Administration Fig. 2 The brochure distributed by the Swedish Telecommunications Administration when the AXE exchange was to be put in service The Swedish telephone network is to undergo a considerable renovation The telephone exchanges will therefore be replaced by new, computer-controlled exchanges that will permit a large number of new telecommunication facilities for the subscribers in the future. The work will start here in Sodertalje on March 1st this year, when approximately 3000 telephones in the number series 30 000 - 32 999 will be switched over to a computercontrolled telephone exchange AH the changeover work will be carried out at the telephone exchange, and it will not be necessary to change your telephone set The new telecommunication facilities will be introduced gradually and the immediate changes will be that • the dialling tone comes quicker D the pitch of the signal is changed • the ringing signal comes every 6th second instead of every 10th • the reference tone is changed to a triad The next stage of the modernisation program is planned for the second half of 1978 All telephones in Sddertalie with numbers that start with 1. 3, 6 or 8 will be connected to the new telephone exchange in 2-3 years At that time it will also be possible to obtain all the new telecommunication facilities. We will be contacting you again later on and we will then be explaining what these facilities are and how they function. THE TELECOMMUNICATIONS ADMINISTRATION Sodertalje — that the operational reliability of the exchange met the set requirements — that the traffic with interworking exchanges functioned satisfactorily — that the operating instructions provided took into account all the operating routines — that in other respects the exchange was ready to be taken into service. Execution The field trial started with the loading of the exchange and subscriber data required for operation. The exchange was loaded with internal traffic as well as traffic to and from interworking exchanges. It was considered as being in service, and thus all handling was done in accordance with the applicable operating and maintenance routines. The field trial comprised some 30 different activities, which were carried out mainly during the daytime. During the night the exchange was unmanned, with the remote alarm system connected to the Stockholm maintenance centre. Some of the most interesting trial activities were: a. Supervision of test traffic. This comprised the reading or checking of — the counter for the subscriber traffic generator — call connections — the results of the weekend tests described below — the results of the supervisory tests that were carried out — fault printouts (that they were obtained). It also included keeping a journal of fault printouts and any measures required to correct faults. b. Weekend tests, an unmanned longterm test that was started on the Friday evening and finished Monday morning. Test traffic, traffic recording and supervision functions were connected in during this test. c. Traffic recording for verifying the test traffic and traffic recording functions d. Alarm and alarm transmission for checking local alarm functions and the transmission of alarms to a superior centre. e. Regular charging output for checking that the charging was correct. f. Fault diagnosing, repair and repair checking in connection with the simulation of — permanent faults in the synchronously duplicated central processor — permanent faults in the current feeding — permanent faults in memories — temporary faults in various devices. Activity f. comprised checking that the automatic fault analysis functioned properly by giving the expected fault printouts, and also that the operating instructions were adequate. The faults that were detected during the various stages of the field trial were corrected as they arose. Result The faults were recorded in a journal and divided into categories, such as service quality, system restart and breakdown. The Telecommunications Administration had set requirements for each category in the form of the maximum number of permitted faults or maximum loss of traffic. The test showed that these requirements were met with a good margin, and as a result it was decided to put the AXE 10 exchange into service on March 1 st, 1977 at 4 a.m. Putting into service and subcriber reactions When the exchange was put into service, 3000 subscriber lines from the AGF exchange were connected in. The number series in question included 2430 ordinary subscriptions and also PABXsubscribersandthree-coin instruments. Before the exchange was put into service all subscribers had received a leaflet from the Administration's Sales Department with diverse information concerning the changeover, fig. 2. The changeover was planned down to the last detail. Naturally the morning
Page 1: ERICSSON REVIEW 1 1978 OPERATIONAL
Page 5: ERICSSON REVIEW NUMBER 1 • 1978
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 and 16: Stored Program Controlled PABX, ASB
Page 17 and 18: 13 When the receiver is lifted the
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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