Nortel Networks DCT1900 User Manual
Technical Product Manual - DCT1900
System Description, Radio Exchange Boards
4-8
System-DCT1900/R8/mw
© 2000-2005
4.8
Digital Trunk Unit-DTU-T1 CCS ( REX-BRD0025 or 2/ROFNB 157 13/3 )
The DTU provides the digital interface between the MS and the RE. The physical connection with
the MS is established via 100 ohm twisted pair cables.
the MS is established via 100 ohm twisted pair cables.
Every DTU board contains 2 DTCs (see Figure 4-7), each equipped with identical firmware. Both
DTCs support the Common Channel Signalling (CCS) interface.
DTCs support the Common Channel Signalling (CCS) interface.
Each CCS interface provides 23 (total 46 per board), communication channels to which Portable
Telephones are assigned dynamically. These channels are shared by the Portable Telephones
which means that although the RE can handle more Portable Telephones, only 23 calls per CCS
interface can take place at the same time. However, there is a maximum of 60 concurrent off
hooks and a maximum of 2 DTU-T1 (CCS) cards per mobility RE.
Telephones are assigned dynamically. These channels are shared by the Portable Telephones
which means that although the RE can handle more Portable Telephones, only 23 calls per CCS
interface can take place at the same time. However, there is a maximum of 60 concurrent off
hooks and a maximum of 2 DTU-T1 (CCS) cards per mobility RE.
Fig. 4-7 DTU-T1 CCS
DTC2
L1
DTC1
BC
BC
Channels
24 - 46
Channels
1 - 23
1.544 Mbit/s
Trunk
1.544 Mbit/s
Trunk