Chapter 5. Configuration Menu61202129L1-1TSU 120 User Manual5-7Base DSX-1 TimingThe PBX is the source of timing. The TSU 120 uses the clockderived by the Base DSX-1 interface for transmission timing.SeeFigure 5-3.Figure 5-3.DSX-1 Timed Clock SourceDTEOSC(OPTION)NetworkInterfaceT1 XMITT1 Receive( D S 1 )Nx56/64DTE CLOCKDSX-1PBX