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Stored Program Controlled
PABX, ASB 100
Per Furu
In connection with the modernisation of their PBX range LM Ericsson, in cooperation
with ELLEMTEL and the Swedish Telecommunications Administration,
have developed an electronic, stored program controlled PABX for up to 100 extensions.
The objectives of the development work were to develop an easy-to-handle
system with the greatest number of functions that the economic aspects allowed.
Special importance was attached to achieving a system that works with good
economy during the whole of its life as regards operation, maintenance and
administration.
The operator's set has been given a new design in order to simplify the handling of
calls. In addition to normal tasks the operator also has the possibility of carrying out
a part of the administration and supervision of the PABX.
UDC 621.395 24
ASB 100 is a stored program controlled
PABX system with the programs stored
in a permanent semiconductor memory
(PROM) and data stored in an electrically
changeable semiconductor memory
(RAM). The PABX is equipped with a
single stage, non-blocking switching
network with full accessibility between
extensions and the devices that carry
traffic.
ASB 100 is available in two different
cabinet heights depending on the final
capacity required. The smaller cabinet
can be built out to 40 extensions and the
larger cabinet has a final capacity of 100
extensions. The system has a high traffic
handling capacity in both cases.
The PABX is built up entirely of printed
board assemblies, which are mounted in
shelves in the cabinets. The wiring is
carried out in a rear plane that is common
for three shelves. The smaller
system contains one such unit and the
larger contains two. These units, and all
external units, such as extensions and
external lines, are interconnected by
means of standardized cables equipped
with plugs.
The system can be delivered to the
customers as a complete, tested unit,
which reduces the installation time considerably.
Stored program control has made it
possible to introduce a large number of
new functions, which have previously
been available only in large systems.
The aim has been to provide these functions
solely by additions to the software,
as far as this is possible, and to avoid
special equipments, wiring changes and
special apparatus. However, space has
been prepared in the rack for those
functions that require extra equipment,
and consequently a function can be introduced
quite easily at any convenient
time.
The PABX permits any combination of
Fig. 1
ASB 100. Operator's set and cabinet for 100 extensions