TELE-X - a Satellite System for TV and Data Communication ...

The central software consists of a number
of program modules, each of which
handles one or several functions. Modules
have been developed for, among
others:
- Operating system
- Loading
- Control program
- Fault handling
- Statistics
Fig. 3
LPB 110
System structure
LPB 110 consists of hardware and software,
and is controlled by microprocessors,
fig. 3. The system has a
modular structure both as regards functions
and capacity, which means that
new functions can easily be added.
The software is stored in RAMs which
are loaded from floppy disc units. The
use of RAM makes the system very flexible.
When programs are updated new
floppy discs are sent to the users.
CPU contains administrative routines,
statistics and I/O functions. Slave processors
are used to relieve CPU of certain
scanning routines in the interface
hardware.
LPB110 consists of a central part, one
or more application parts and an I/O
part, fig. 4.
Central part
The central part in LPB 110, fig. 5, is a
computer system developed by Ericsson,
APN167, which has a Motorola
68000 as CPU. The programming language
is a high-level language. ERIPAS-
CAL, which is a Pascal language adapted
for real-time app I i cat ion. In addition a
control language has been developed
with which the users of LPB 110 can program
their own test sequences. The execution
of test sequences controls the
I/O
The I/O units in LPB 110 are portable
typewriters, and two floppy disc storage
units for 51/4" discs, fig. 6. Interworking
with the AXE 10 system takes place via
a signalling interface (CCITTV.24). The
I/O system of the AXE 10 exchange can
therefore be used to communicate with
LPB 110. All program modules are
stored on floppy discs, and they are automatically
read into LPB 110 when the
system is started up. A built-in editor
enables the user to design new control
programs or modify the supplied programs.
Application part
Special hardware and software has
been designed for use in LPB 110 as interface
to different signalling systems.
An interface can be used for more than
one signalling system. For example, the
same interface module is used for both
CCITTR1 and R2, fig.7.
The hardware can be controlled via one
of two buses, either the I/O bus of
APN 167, which is used in new designs,
or the EM bus in AXE 10 via a specially
developed bus interface.
When the EM bus is used LPB 110 can
utilize the hardware in AXE 10 (for example
the signal ling terminal for CCITT signalling
system no. 7).
Each hardware interface has a diagnostic
program, which monitors the connected
hardware and initiates a printout
if a fault should occur. The faulty board
can then be changed.
Traffic functions
In LPB 110 each test object is considered
as a control individual, for example