User manual

Chapter 5. Configuration Menu
5-4 TDU 120e User Manual 61202156L1-1
TDU 120e Clock Sources
The TDU 120e is operable from various clock sources,
permitting it to perform properly in many different
applications. Set the network interface clocking options with
the clocking options set by the Network (NI) Configuration
menu options.
The following clock source options are available:
• Network Timed
• Base DS-1
• Base DTE Timing
• Internal Timing
• Secondary Timing
• Normal (CSU)
• U-BR1TE
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 loop timed as the transmission clock is derived
from the received clock. See Figure 5-2.
Figure 5-2. Network Timed Clock Source
The selected clock option always designates the clock source for
transmission. Clocking necessary for receiving data is always re-
covered from incoming data.
DTE
OSC
Secondary
Interface
(OPTION)
Network
Interface
T1 XMIT
T1 Receive
(DS1)
Nx56/64
DTE CLOCK
DS-1 PBX
PBX