White Paper
LinkSYSTER - White Paper / The principal
Why we developed the LinkSYSTER.

It sound like a very simple function. But, it was something many have
looked for and have had hard to solve. Often engineers, service
people, quality people, field workers and even ordinary consumers use
a stright serial RS232 connection. It might be between a
terminal/computer and a remote unit, a microprocessor and a
programmer, a wheighing system and a computer, a logger and the
diagnostic analyzer and many similar units. In conclusion, there are
two units communicating over a serial RS232 wire.

If the units support modem comminication it is possible to replace the
cable by two cellular modems. But if not? To connect a cellular modem
to something sensitive and protocol dependent is often not possible.
We saw this demand and solved it. We give a transparent link and
replace the wire. We even made it better for we treat the line as not
connected until the remote unit says it will be virtually connected.

Why not just a pair of cellular modems?

First the units must support AT-commands and accept the dial up
dialogue. Usually the connection phase also disturbs the external
units. That's why the units must be prepared for modem
communication. Consequently standard cellular modems are not a way
to go. Beside this we also added security functions to protect the
connection as well as remote control of connect and disconnect. Still
the link is transparent. We don't send out any unwanted characters
and when the "line" is connected we don't add anything. Thus the
units can have a built in protocol and still do fine within this link
between LinkSYSTERs.

What is the advantages?

In principle three. It gives the possibility to do wireless communication
between units that are made only for direct wire serial connection. A
service engineer can supply remote support/analyze/service to an
external unit far away from him. The alternative has been to be out,
with all the consequences of cost and consumed time.

The second advantage is, in principle, real-time connection. In many
cases this is very important and useful. Like when you would se the
result the same time it happens. It is also an important advantage in
precision positioning or to identify vehicles.

The third advantage is the secured access to the link.

How did the idea about LinkSYSTER come?

It was a combination between the long experience we have of our
other SYSTERs and demand from our customers. Simply we have been
missing this kind of product. When several companies told us it was
very easy to see the need. Then it was more a technical question.

The platform of LinkSYSTER.

LinkSYSTER is the first in a line of new products based on our new
SYSTER platform. It is a microprocessor based communications unit
with possibility of twin powerful processors and a number of special
circuits. Added to this we have the possibility to define the processor
board by add or remove components. There are also around twenty
bridges we can make to define the functionality. At last, and the most
important, is the modularity in firmwares to the different processors.
We simply have the possibility to fast and reliable develop new codes
and functions.

The result gives a way to develop a wide range of products based on
the same main concept. Of course it gives products with a more
attractive price than if we develope separate products. It also gives
the advantage of a stable firm- and hardware faster in the
development stage. Our earlier SYSTERs has been steps in this
direction, and wellknown for it, but we have never been so far into it
as now.

Thus the LinkSYSTER is the first of a line of products based on this
concept. Even if the following SYSTERs will be very "look alike" the
functionality will be different. It depends on the the processors,
wireless network (GSM, 3G, CDMA, TDMA, CDPD, Mobitex, GPRS or in a
SMS functionality), and what the firmwares tells the product to do. All
from a link to measurments and alerts. The prename ('link') will tell you
the difference.

To work with LinkSYSTER

The LinkSYSTER is very easy to work with. You know it it gives a
transparent link between two units. If you compare the input on one
of them with the output on the other, you can't see any difference
with a cable. The difference is you can define "the other side of the
cable". Thus it can be in the same house, in next community or in a
different continent.

The functionality is the firmwares in the LinkSYSTER. In addition you
can do user settings. It is done with commands from a standard TTY
terminal (like TTY/VT52/VT100 or Windows terminal).

To establish connection you just give the telephone numer to the unit
you will have a link with. After some preprogrammed routines
(connection and security) a LED function on the LinkSYSTER will sign a
transparent link is established. You can now connect whatever you
like in equipments or applications.

During the link establishment there are no unwanted characters sent
out to your slave unit so the running process out there will not be
disturbed. It is very important in e.g. monitoring an logging.

The LinkSYSTER itself now monitor the link to see all is working
properly. As long as the network accept the connection (the phones
are working) the LinkSYSTER keeps the link open. Disconnect is done
on time-out (no one is using the line in a certain time, by setting) or
you hit the push-button 'disconnect'.

One LinkSYSTER can establish links to several others but just one at a