Elcon Elconnect Coax Client VoIP, Operating Instructions Manual, Page: 19 / 32

Client VoIP
f in MHz
4 34
47 860
Pay-TV
Fig. 3: Frequency allocation in consideration of the pay-TV signals;
Frequency notching
To prevent interferences to the pay-TV system, the Coax system must cut the frequency range
around the charging channel („notching“). This can be realized by a special modem configu-
ration, which reduces the net data rate by ca. 15%. It might be that further measures have to
be taken, such as lowering the devices´ transmit level (which affects the operating range), or
the insertion of additional filters in front of the pay-TV equipment inlet.
The data signal is bidirectionally transmitted via the cable TV distribution network. The coax-
ial cabling setup (e.g. in tree or star structure) is uncritical. All modems have equal access
rights to the medium. The transmission uses a multiplexing procedure, allowing for an auto-
matic data rate adaptation, subject to the connection quality. This both robust and effective
transmission method offers a reliable data transfer even under the most difficult circum-
stances. When several units are used, the data rate is dynamically shared.
The Master represents the interface between the unidirectional "television" of the cable TV
distribution networks and the bidirectional "Internet access" provided by the telecommunica-
tions network. For example, the Master can be linked to a router, thus feeding the data signal
after the in-house amplifier (optional via the provided diplex filter) into the house distribution
network. The signal is then distributed to all TV outlets installed within a radius of max.
750 m (depending on the environment). Through the TV splitter (included in delivery) the
signals from the Clients are supplied to the TV socket in the client´s flat. This can be easily
done without requiring further costs, since all the needed components are included in deliv-
ery. The Client is connected with the network interface card of the PC via a patch cable. So
the client can use the "Internet access" without any further configuration of the personal com-
puters to be linked.
The ELCONnect coax modems are responsible for processing and modulation of the data
transmitted through the coaxial cable network, as well as for the provision of all interfaces for
Ethernet and coaxial link.
Thanks to their functionality, the modems, after being connected to a server or router (Master)
or, respectively, to the network interface card of the relevant PC or router (Client), are used
both as transmitter and receiver of the information to be exchanged. Hereby the ELCONnect
coax system functions as bridge between server or router, on the one side, and the terminal
equipment, such as PC or set-top boxes, on the other. IP addresses, for example, are dynami-
cally (DHCP) or statically allocated by the server or router to the linked terminals (PC) the
same way as it is normally done within a standard PC network.
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Version: 2009/09/01