geostationary telecommunications satellites electronic telephone set ...

Development, Production and
Maintenance of Software
for AKE 13
Lars-Olof Noren and Siwert Sundstrom
Transit exchange system AKE 13 and its software have been described
in earlier articles in Ericsson Review^- 2 , and also methods and support systems
for testing the software 3 .
The article gives an insight into the development, market adaptation, production,
installation and maintenance of the software. It is important for a modern
telephone exchange system that these activities are organized logically and that
the system is able to satisfy the various demands made on it.
signals, and for making and executing
logic decisions, are realized in programs.
These are stored in the common
control store together with data
concerning the build-up of the exchange
and network and about the upto-date
status of the connection sequences.
The structure and function of
the programs was described in an
earlier article 2 .
UDC 621.395.722:
658 581
LME 66
Transit exchange system AKE 13 is a
SPC system, fig. 1, that has been developed
by LM Ericsson. The basic functions
of the systems are already fully
developed and in operation, but further
development of various functions is
going on all the time. The system is
adapted to new market requirements
by the addition of new basic functions,
and above all in the form of the addition
of new signalling systems when
the system is introduced on new markets.
Since the control logic in a SPC exchange
is realized mainly in software,
new development work consists mainly
of software design. Hence LM Ericsson
have a staff of software designers
both in the parent company and the
subsidiary and associated companies.
Broadly speaking, the work has been
allocated so that the designers in the
parent company program various general
functions while the subsidiary and
associated companies program the
functions that are specific for their
particular market, for example signalling
functions.
Support system APT has been developed
for the production of software.
However, the support functions are
not only used for design and the associated
testing of new software, but
also for all subsequent handling of the
software, comprising production of
program and data packages for the
different AKE exchanges and administrations,
and for the maintenance of
a comprehensive program library.
Software and documentation
In a SPC system all functions for storing
and interpreting control and state
In the following description programs
and data are summarized under the
concept software.
The software must obviously be documentated
just as carefully and well
organized as the hardware. It has proved
to be rational to document and
register software products according
to the same rules as other articles in
the LM Ericsson product range.
The basic unit in the system is called a
function block or often just block. The
block contains program sequences
with functionally associated data and
hardware units. For example, all program
sequences and data records that
are used for signalling in a certain type
of code receiver, together with the
code receiver itself, constitute a code
receiver block.
Each block is described in a set of
documents, which are brought together
in a document summary. The
medium that is used for a certain document
can vary depending on where
the document is used. Thus certain
documents, forexample program code,
are stored on magnetic tape, whereas
others are printed and are available in
book form, for example operational instructions.
Like all other products, during its lifetime
the software undergoes a number
of changes because of modifications,
function additions etc. Each time there
is a change of the block program code
the block is given a new revision state,
which is entered in the document
summary, which also includes information
regarding which documents have
been revised. The document summary
thereby unambiguously defines the
document set that applies for a certain
revision state in the block.