When the administrative information is transmitted by Infrared Communication, the leakage of it is the serious cause of anxiety. There is not the detail explanation about the security in your home page. I want to know the technical explanation why there is no leakage.
When the administrative information is transmitted, we must examine both
of the transmission method and the physical layout.
||The transmission method of the information is supposed as follows.
||Cable Communication of metal wire or optical fiber
||Radio Wave Communication
||The physical layout (topology) is supposed as follows.
||Point to Point (P-P) : Connection of center and repeater, for example the
||Point to Multi-Point (P-MP) : Connection of HUB and plural nodes, for example
When the combination of (A) and (B) is examined, the examination points
are the simplicity of setup, the communication speed, the reliability and
The topology of Infrared Communication is as follows.
- P-P : Outdoor Communication between equipments 1`2km apart
- P-MP : Indoor Communication between HUB and plural nodes in 10m radius
The reason of the high security is different respectively.
In the case of (1), the high security is maintained because the laser beam
has the sharp directivity different from radio wave and the beam axis must
be coincident with each other for the normal communication.
Infrared Communication transmits the concentrated beam to the opposite
equipment. Illegal receiver can be detected because it must be setup on
the communication route for the tap and the beam axis adjustment is also
needed. In the case of Radio Wave Communication, there is the side lobe
component from antenna and the radio wave beam is not so sharp as Infrared.
The tap is difficult in the case of Infrared Communication.
In the case of (2), the high security is maintained because the beam can not pass through the wall for the communication between HUB and plural nodes. The signal does not leak from the room.
The above explanation is for the security against the illegal reception
in the free space. But the security level of the electrical signal converted
from Infrared is the same as optical fiber and radio wave.