LDCMLD CMLDCMLDCMLDCMLD CMLDCMLDCMLD CMLD CMLDCMLDCMLDCMLDCMLDCMLDCMen06000519-2.vsdIEC06000519 V2 EN-USFigure 115: Direct fiber optical connection between two IEDs with LDCMThe LDCM can also be used together with an external optical to galvanic G.703converter as shown in figure 116. These solutions are aimed for connections to amultiplexer, which in turn is connected to a telecommunications transmissionnetwork (for example PDH).Telecom. Network*) *)Multiplexer Multiplexeren05000527-2.vsd*) Converting optical to galvanic G.703IEC05000527 V2 EN-USFigure 116: LDCM with an external optical to galvanic converter and amultiplexerWhen an external modem G.703 is used, the connection between LDCM and themodem is made with a multimode fiber of max. 3 km length. The IEEE/ANSIC37.94 protocol is always used between LDCM and the modem.20.1.3 Setting guidelines M12454-3 v764 kbit and 2 Mbit mode common settingsChannelMode defines how an IED discards the LDCM information when one ofthe IEDs in the system is out of service: it can either be done on the IED out ofservice by setting all local LDCMs to channel mode OutOfService or at the remoteend by setting the corresponding LDCM to channel mode Blocked. If OutOfService1MRK 511 407-UEN C Section 20Remote communicationPhasor measurement unit RES670 2.2 IEC 325Application manual
