Nortel Networks DCT1900 - Manual (Page 205)

Technical Product Manual - DCT1900
Installation Instructions, Digital Trunk Unit (DTU–E1) – REX-BRD0002 or 2/ROFNB 157 13/1
Install-DCT1900/R8/mw 11-1
© 2000-2005
C HAPTER 11
Digital Trunk Unit (DTU–E1) – REX-BRD0002 or 2/ROFNB 157 13/1
11.1 General
The DTU–E1 provides 60 communication channels via two 2 Mbit/s links.
Maintenance
The DTU–E1 has the following field–exchangeable parts (see Figure 11–2 for placement &
orientation):
z DTU–E1 CCS Firmware Set NTM/RYSNB 101 17/3
z DTU–E1 CAS Firmware Set RYS 105 664
z The DTU–E1 Firmware Set is delivered as a separate item
11.2 Board Description
The DTU–E1 Board contains two identical DTCs (DTC1 and DTC2), each with their own identical
connectors and LEDs.
Straps
By means of straps, the type of cable to be used can be selected: coaxial pairs or 120 ohm twisted
pairs (symmetrical). In Figure 11–1 an overview of the strap settings is given, for the location refer
to Figure 11–2.
Note:
The straps should be placed in the twisted pair position (120
Ω).
Fig. 11–1 Strap Settings DTC1/DTC2
Connectors
The DTU–E1 board has 4 connectors at the front, two for each DTC. One is for coax cable and the
other one is for twisted pair cable connection. See Figure 11-2.
Coax/twisted pair straps
DTC1 and DTC 2
Coax (connection closed)
Twisted pair (connection open)
Not allowed
Not allowed