A case study: DX 200 Exchange (cont.)
nBCDU:Basic Data Communication
Unit: Serves various data services to OMU as access to X.25 and LANs
nM:
Marker Unit: Controls concentrators / space switches
nCM: Central Memory: Contains user
database, charging, signalling,
routing and exchange ensemble.nSTU: Statistical
Unit: Collects statistical information on traffic and charging.nCHU:Charging Unit: Maintains charging
database obtained from
signalling units.nOMU:Operation and Maintenance Unit: Allows personnel access to
exchange memory, perform tests an traffic measurements.