Nortel Networks DCT1900 - Manual (Page 44)

Technical Product Manual - DCT1900
System Description, Radio Exchange Boards
4-6 System-DCT1900/R8/mw
© 2000-2005
4.6.2 CAS - REX-BRD0002 or 2/ROFNB 157 13/1
DTU-E1 CAS is used only in standalone configurations. The DTU provides the digital interface
between the PBX and the RE. The physical connection with the PBX is established via twisted
pair cables.
Every DTU board contains 2 DTCs (see Figure 4-5), each equipped with identical firmware. Both
DTCs support the Channel Associated Signalling (CAS) interface.
Each CAS interface provides 30 (total 60 per board), communication channels to which Portable
Telephones are assigned statically. Each channel is dedicated to a specific Portable Telephone
number. The maximum number of Portable Telephones a RE can handle is 600. This is
supported on 10 DTU E1 CAS cards.
Fig. 4-5 DTU-E1 -CAS
L2
DTC2
L1
DTC1
BC
L2 L1 BC
Channels
31 - 60
Channels
1 - 30
2 Mbit/s
Trunk
2 Mbit/s
Trunk