EXPRESS DAS
Installation and Operations Manual
EXPRESS DAS Installation and Operations Manual – Version 2.2 November 2013
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6.2.2
Donor Optic Unit
Within the OEU, converting RF signals to optical signals and back again is the job of the Donor Optic
Units (DOUs). Each OEU can support up to two DOUs. Each DOU supports four optical ports, providing
connection for up to eight MRUs. The DOU used in the OEU is the same unit as found in the ODU. See
page 30 for more detail.
6.2.3
Extension Wavelength Division Multiplexer (EWDM)
The EWDM module converts the downlink signals (optical to electronic) and also the uplink signal
(electronic to optical). An FSK modem provides communication with the BIU, and an attenuation feature
can compensate for optical cable loss between ODUs. The EWDM has internal wave division multiplexing
(WDM) functionality allowing it to connect to MRUs/ARUs through a single optical cable.
6.2.4
Expansion Central Processor Unit (ECPU)
The ECPU monitors and controls the status of the modules installed in the OEU. This unit communicates
with and acts as a bridge between the BIU and MRU.
In addition, the unit has an USB-B port for connecting a PC and controlling system devices. At the front
panel, an LED indicates the communication status with the BIU and the MRUs/ARUs. It also has ALM
LED indicator to show if a device is faulty.
6.2.5
Expansion Radio Frequency Module (ERFM)
The ERFM reconstructs downlink and uplink signals that may have been degraded by the optical modules.
This module communicates with the MRU through an internal FSK modem.
6.2.6
Expansion Power Supply Unit (EPSU)
The EPSU acts as a DC/DC Converter. The unit receives -48V and de9V and +6V of DC power
required for the OEU.
NOTE
: The EWDM, ECPU, ERFM and EPSU are factory installed and not field replaceable. If you
suspect this unit is not operating properly, contact SOLiD support.
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