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

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The following tests can be made:
• Measurement of dial pulse speed, nominal speed — 10 Hz
• ,. „ „ ,. ,. „ „ = 20 ,.
• Testing of bell with full ringing voltage, continuous signal
• half ,, ,, intermittent ,,
• Measurement of insulation resistance of a-wire to earth
• „ „ „ ., b-
• ,. ,, „ „ between a-wires and /'-wires
• ,, ., line resistance.
The result of the test is delivered from APR in the form of buzzer tone.
If a measurement of the dial pulse speed has been made, three different tones
can be obtained, indicating normal, too slow or too fast dial.
Equipment for Traffic Measurement
For continuous supervision of congestion, permanent congestion counters
are connected to every route and 80-line group. If extended supervision of the
routes is required, a special relay set, TMR, can instead be connected per 80line
group. This relay set is available in three types, for 5. 10 and 20 routes.
When TMR is used, a record is also obtained of the number of occupations
per route and 80-line group, the number of calls lost owing to congestion per
route and five 80-line groups, and the number of occupations per alternative
route and five 80-line groups.
The traffic intensity, TKT, is measured with an automatic traffic meter.
Depending on the size of the exchange and the desires of the administration,
this traffic meter can be either permanently installed or portable. TKT wires
from 20 devices are interconnected into a group on the IDF. Connection to the
jack of the traffic meter is thereafter done in such a way that if possible, all
devices of the same type, e.g. SR, can be measured simultaneously.
The traffic meter measures the number of occupied devices in every group
100 times during an hour. On every measurement the number of occupied
devices in the group is recorded on individual counters. The meter can be
started and stopped automatically. The number of counts can be preset on
a zeroable counter.
The permanently installed traffic meter can at the same time measure the
traffic intensity of 20 • 60 devices and consists of relays for automatic connection
of the TKT wires, measuring equipment and counters for the groups
of devices to be measured.
With an auxiliary unit TMVR four different programmes can be selected
with keys, with 1200 devices in each programme.
The number of occupations, TKM, is measured on separate counters. For
measurement of TKM during the same period as TKT, the voltage to the TKM
counters is steered via a relay into the traffic meter.
The portable traffic meter (fig. 19) is assembled in two portable cases, one
of which contains the measuring equipment and the other the TKT counters.
This meter can simultaneously measure the traffic on 20 devices in 45 groups,
i.e. 900 devices. Jn one type of this traffic meter the meters have been replaced
by a tape punch. A code is punched on the tape, indicating the number
of occupied devices in each group at the time of measurement.