Nortel Networks DCT1900 manual DTU-T1 CCS

Technical Product Manual - DCT1900

System Description, Radio Exchange Boards

4.8Digital 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.

Every DTU board contains 2 DTCs (see Figure 4-7), each equipped with identical firmware. Both 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.

BC

BC

DTC2

L1

Channels

24 - 46 1.544 Mbit/s

Trunk

Channels

1 - 23

1.544 Mbit/s

Trunk

DTC1

Fig. 4-7 DTU-T1 CCS

4-8	System-DCT1900/R8/mw
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