ADTRAN 1200060L1, User Manual

Page: 24 / 78

Chapter 1. Introduction
1-8 TSU User Manual 61200060L1-1
TSU Clock Sources
The TSU 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
Network (NI) Configuration menu options. There are three
clock source options available.
• Network
• DTE Timed
• Internal Timing
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.
Figure 1-4. Network Timed Clock Source
The clocking option selected always designates the clock source for
transmission. Clocking necessary for receiving data will always be
recovered from incoming data.
OSC
NX56K/64K
DTE CLOCK
DTE
Network
Interface
T1 XMIT
T1 Receive
( D S U )