Issue 5     November 2000   
363-206-208
Introduction
Lucent Technologies - Proprietary
See Notice on first page
circuit packs and the FN circuit packs. The TSI circuit packs also take a 51.84 Mb/s 
clock signal and an   8 kb/s frame synchronization signal from the TGS circuit pack and 
distributes them to the MAIN OLIU and FN circuit packs. The TSI-1 is dedicated to the 
Main-B-1 OLIU and TSI-2 to the Main-B-2 OLIU. The BCP3 TSI circuit pack provides 
flexible STS-1 cross-connect capability.
Located to the left of the TSI circuit packs are two MAIN OLIU circuit packs. Each MAIN 
OLIU will receive 12 STS-1 signals, perform frame alignment and pointer processing, 
and map them into 1 STS-12 signal. This STS-12 signal is then converted to an optical 
signal and transmitted to the far-end via single mode fiber. The OLIU also receives an 
OC-12 optical signal and demultiplexes it to 12 STS-1 signals which are then routed to 
the TSI circuit packs. Each OLIU is a bidirectional circuit pack. There are two OLIU 
circuit packs to provide to provide path protection switching. 
Located at the top of the OC-12 shelf are two TGS timing circuit packs. These circuit 
packs will provide a 51.84 Mb/s clock signal and a 8 Kb/s frame synchronization signal. 
The timing packs are 1x1 protected. 
DDM-2000 OC-12 Fan Shelf Description
Forced air cooling is always required for the DDM-2000 OC-12 multiplexer shelf. The  
DDM-2000 fan shelf, ED-8C733-30, G8, provides forced air cooling for DDM-2000 
OC-12 shelves that are bay mounted in a controlled environment [for example, central 
office (CO), controlled environment vault (CEV)]. 
The number of fan shelves required in a bay is determined by the number of DDM-2000 
OC-12 shelves in the bay (each shelf requiring a fan shelf). Refer to the “Equipment and 
Rear Access Cable Installation” or “Equipment and Front Access Cable Installation” 
section of this manual for fan shelf requirements.