Nortel Networks DCT1900 manual DTU-E1 CCS

Technical Product Manual - DCT1900

System Description, Radio Exchange Boards

4.6Digital Trunk Unit - DTU-E1

4.6.1 CCS - REX-BRD0003 or 2/ROFNB 157 13/6

The DTU provides the digital interface between the MS and the RE. The physical connection with the MS is established via twisted pair cables.

Every DTU board contains 2 DTCs (see Figure 4-4), each equipped with identical firmware. Both DTCs support the Common Channel Signalling (CCS) interface.

Each CCS interface provides 30 (total 60 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 30 calls per CCS interface can take place at the same time. The maximum number of Portable Telephones a RE can handle depends on the GOS (grade of service) and the traffic capacity of the RE configuration. However, there is a maximum of 60 concurrent off hooks and a maximum of 1 DTU-E1 card per mobility RE.

BC

BC

DTC2
L2	L1

L2	L1
DTC1

Channels 31 - 60

Channels 1 - 30

2 Mbit/s Trunk

2 Mbit/s Trunk

Fig. 4-4 DTU-E1 CCS

System-DCT1900/R8/mw	4-5
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