User Manual

ArchitectureNortel Networks Confidential 3–7
S8000/S8002/S8006 BTS Reference Manual
3.1.3.4 Internal PCM bus
Principle
The V11 bus is located between the switching matrix and the following units:
PCM Interface units (PCMI)
Data Signaling Concentration units (DSC)
GaTeWays (GTW)
The 16 internal PCMs are synchronous links at 2 Mbit/s on which the data are
organized in 125–µs frames divided into 32 time slots of eight bits each. A PCM
is a time division multiplexed link that supports 32 channels with a throughput of
64 kbit/s.
Interface signals
The signals used are the following:
• MICR : Receive PCM in master–to–slave direction
• MICE : Transmit PCM in slave–to–master direction
• SY : 8 kHz negative frame synchronization pulse
• H4M : 4.096 MHz timing clock
3.1.3.5 O&M bus
Principle
The O&M bus is a V11 asynchronous master–slave type bus that is subject to
physical addressing. It interconnects all units of the BCF subsystem and the TXs
through the private PCM between the GTW and the DRXs. The CSWM acts as
master.
The bus enables users to do the following:
set up the initial configuration and reset it
measure and control system status
retrieve alarms
force each bus subscriber to “RESET” status
Interface signals
The O&M bus is used in the BCF and originates from the CSWM card. Due to its
low rate (9600 bit/s), this bus is not matched.
The O&M bus contains ten logical signals: