Reference Manual

Table Of Contents
Product Description 8 (33)
© Ericsson. Commercial in confidence Rev B 2001-05-16 SRN/X-00:146
Internal Distribution Module (IDM)
The IDM handles the distribution and fusing of the system voltage (+24 VDC) to the units
in the cabinet. There is a connector for connection of ESD bracelet and instrument
electrical earth on the IDM.
Double Transceiver Unit (dTRU)
The dTRU is a two-transceiver Replaceable Unit. Up to six dTRU units can be installed in
one RBS 2106 cabinet, enabling up to 12 TRXs per cabinet.
Figure 4. Double Transceiver Unit.
There are different versions of the dTRU dependent on frequency band and EDGE
support. All dTRUs are HW prepared to handle HSCSD and GPRS, the EDGE dTRU is
HW prepared to also handle the ECSD and EGPRS functionality.
The dTRU supports different ciphering standards. Either A5/1 or A5/2 can be used. The
ciphering is controlled via software.
A hybrid combiner is included inside the dTRU. The combiner can be used, optional,
together with CDU-G to increase the number of TRXs per antenna. It is possible to by-
pass the hybrid combiner by connecting a cable in the front of the dTRU.
Extended Range up to 121 km is supported.
The dTRU is hardware prepared to support performance improvements via software
upgrades, e.g. four-branch RX diversity and Enhanced Interference Suppression (EIS).