Contents Telektronikk - Telenor

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(a)
1 2012136 0 086 0 024 Z 0 YYY Y XXXX A 00
External
Indicator 1)
Charging units
1/10 min
Minutes Call holding time
Hours
Minute
Time
Hour
Day
Date
Month
1) Z=A: Set up manually
Z=D: Call holding time>10 hours
Z=G: Alternative selections
Z=L: Conference call
Figure 1 A typical record in a charging file
period” (i.e. not close to vacations) we
decided to analyse data from Period 1 in
more detail. The results from Period 2 are
used to check the results from Period 1.
By using TELMAX some additional
information is obtained. The measure-
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(b)
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0000 0400 0800 1200 1600 2000 2400
Figure 2 Mean number of successful outgoing calls per
15 minute intervals. (a) weekdays, (b) weekends
Unknown
Access code
A-number
B-number
ments were taken in the following periods:
- Period 3: Monday 1991.11.25 –
Friday 1991.11.29
- Period 4: Monday 1992.01.13 –
Tuesday 1992.01.14
During Period 3 (which coincides with
the 5 first weekdays of Period 2) the
number of incoming and outgoing call
attempts, and the sum of the incoming
and outgoing traffic were measured between
0900 and 1900. Measurements
during Period 4 were made in order to
get the percentage of incoming calls
using the manual service of the switchboard.
2.3.2 The address groups
In addition to analysis of the total traffic
we also investigated the distribution of
traffic between different address groups.
The constitution of address groups is
based on service types and charging
groups. We also observed the traffic to
the other universities of Norway (Universities
of Oslo, Bergen and Tromsø).
Another interesting task is to find the
percentage of all traffic which goes to
Oslo and its neighbouring counties.
The following address groups have been
defined:
- local calls (within the county limit)
- calls to the neighbouring counties (of
Trondheim)
- domestic long-distance calls
- international calls
- paging
- calls to mobile telephones
- special services numbers (e.g. customer
services provided by Telenor AS,
emergency calls, etc.)
- toll-free numbers,
and, as we mentioned before,
- The University of Oslo (UiO), The
University of Bergen (UiB) and The
University of Tromsø (UiTø)
- Oslo and its neighbouring counties,
which all belong to the address group
“domestic long-distance calls”.
By using the telephone directories from
Telenor and the universities we are able
to map the numbers belonging to the different
categories.
A view of which combinations are analysed
in this study is shown in Table 1.
3 Results and discussions
3.1 Profile of 24-hour periods
All successful outgoing calls are registered
in the charging files. The number of
calls per 15-minute intervals have been
summarised for the two-week period.
Figure 2 shows the time diagrams for the
average number of calls per interval, for
weekdays and weekends, respectively.
(Note different ordinate scales.)
The diagrams show that the call intensity
is negligible between midnight and 0700.
For weekdays the call intensity increases
until it reaches a small peak around 1030.
After a clear reduction during the lunch
period between 1100 and 1230, it increases
again to a higher and longer peak
which continues until after 1500. After
that, the call intensity decreases sharply
until 1700, and continues decreasing
smoothly until midnight.
The observation on the traffic volume
shows the same tendency as that of
number of calls.
Some earlier traffic studies of public telephone
exchanges [5] show a high peak
before the lunch period (between 0900
and 1000) and no distinct peak was
observed after the lunch period. Our
results show a different traffic pattern
than normal public telephone exchanges.
We agree with the explanation given in
[4] saying that many of the users of the