ZyXEL Communications PLA-470 V2 - V3.0.5 Przewodnik Instalacji Pobierz pdf (Strona 165)

Home-Made PLC Repeater

A home-made PLC repeater can be fabricated by using Ethernet PLC modems available in

stores.

All you have to do is to take two Ethernet PLC modems and connect them with an

Ethernet cable (crossover or straight-through cable depending on whether the network

interface cards are self-sense cards or not, i.e. that they can adapt or not to network cable

crossover). Two different PLC network keys must then be configured on each PLC modem;

each key is used by the modem for its connection to a part of the PLC network having the

same key (see Chapter 10).

Figure 7.29 illustrates this operating principle.

The two PLC subnetworks communicate between themselves via the repeater consist-

ing of the two Ethernet modems with different encryption keys. However, the disadvan-

tage of this configuration is to reduce the useful throughput of the entire PLC local area

network since the repeater uses the frequency band to regenerate the PLC signal on the

electrical network.

Filters

As indicated before, the electrical network is a communication medium that may be

altered by disturbances originating from the electrical devices connected to it. In par

146 Equipment

Figure 7.28 Example of PLC repeater use

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ZyXEL Communications PLA-470 V2 - V3.0.5 Przewodnik Instalacji Strona 165