ADTRAN TSU 120, User Manual

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Chapter 1. Introduction
61200.129L1-1 TSU 120 User Manual
11
TSU 120 CLOCK SOURCES
The TSU 120 is operable from various clock sources,
permitting it to perform properly in many different
applications. The network interface clocking options
are set by using the clocking options set by using the
Network (NI) Configuration menu options. The
following clock source options are available:
• Network
• Base DSX-1
• DTE Timed
• Internal Timing
• Secondary Timed
• Normal (CSU)
The clock option selected always designates the clock source
for transmission. Clocking necessary for receiving data is
always recovered from incoming data.
Network Timed
The network is the source of timing. The received data
clocking is looped back to the network where it is used
to determine the transmission timing. This option is
also referred to as looped timed as the transmission clock
is derived from the received clock. See Figure 1-4.
DTE
OSC
Secondary
Interface
( O P T I O N )
Network
Interface
T1 XMIT
T1 Receive
( D S 1 )
Nx56/64
DTE CLOCK
DSX-1 PBX
PBX
Figure 1-4
Network Timed Clock Source