User's Manual

Confidential & Proprietary 37/87
5 ERFM
Expansion Radio Frequency Module
Regenerate TX signals and transmit FSK modem
signals;
Regenerate RX signals and receive FSK modem signals
6 Shelf 19” rack, 2U
4.3.4 Function by unit
1) Donor Optic Unit (DOU)
DOU is the same as the module used for ODU.
Figure 4.18 – MDBU Outer Look
2) Expansion Wavelength Division Multiplexer(EWDM)
EWDM module makes optical-electronic conversion of TX signals and makes electronic-optical
conversion of RX signals. With an FSK modem in it, this multiplexer communicates with BIU. It
also has ATT for optical compensation to compensate for optical cable loss between ODUs.
Furthermore, it has internal WDM, and so, it needs only one optical cable to work with ROU.