TechniSat TechniRouter 9/2x4 G - Handbuch (Seite 44)

44
EN
SCR commands can be divided into the following groups:
Channel Change
With this command, the router will be told which SAT IF bank
should be switched to and which channel is to be converted to
the user band frequency.
PowerOff This command prompts the router to switch off the affected user
band.
Installation
There are a number of commands meant to simplify installation of
an SCR system. Thus a receiver can query what kind of router,
LNB or multi-switch, it is connected to, and which LO frequencies
are used. The router answers with an RF signal tone within the
affected user band. In addition, the signal tones for all
participants can be activated simultaneously. This allows
receivers to search for the user bands automatically.
Because there is no bus access control in this system, there can be collisions between
commands sent by more than one receiver at the same time. This problem is solved by the
receivers recognizing the collision and repeating their commands after an ideally random
delay.
7.3 PIN Protection
In distribution systems that have the cable connected to more than one dwelling (Multiple
Dwelling Units, MDU), the SCR commands can optionally be provided with a PIN code.
The command is only accepted if the PIN code matches the one stored in the router. This
should prevent, for example, a misconfiguration from having more than one receiver use
the same user band.
PIN protection can only be used if the installed router supports it. Receivers without PIN
support are usable though. However, commands with PIN codes always have priority.
7.4 Assembly Instruction
As far as the cabling is concerned, besides the series structure, in which all antenna outlet
sockets are on a single coaxial cable harness, tree structures, star structures and
combinations of all three are possible. The important thing is that every single receiver
feeds its control commands via a separation diode into cable sections of the SCR bus
shared with other receivers. This, in combination with the bus voltage being raised to 18V
during SCR commands, is the only way to ensure that these arrive at the router and are
detected within.
Generally, antenna outlet sockets with integrated separation diodes have to be installed.
If one connects multiple receivers to a shared antenna outlet socket, distribution elements
with diode-separated DC paths must be provided.
In contrast to omitted separation diodes, multiple cascaded diodes don't generally impair
the system's functionality. However, in router installations not utilizing an external power
supply attention has to be paid to the resulting lower bus voltage due to voltage drops at
the diodes, whether it is still sufficient for stable operation of router and LNB.