ADTRAN 1200063L1, Manual

Page: 82 / 137

Chapter 7. Configuring DTE Options
7-4 DSU III TDM User Manual 61200063L1-20
Transmit Clock
The T
RANSMIT
C
LOCK
option selects the source of the clock used to transfer
synchronous data from the DTE to the DSU III TDM. Figure 7-3 on page 7-
4 shows the menu path used to set the
T
RANSMIT
C
LOCK
option. The facto-
ry default setting is N
ORMAL
.
Figure 7-3. Transmit Clock Options
To use the internal clock of the DSU III TDM select N
ORMAL
. To use the
external transmit clock from the DTE select E
XTERNAL
.
The
E
XTERNAL
clock option is normally used in modem tail circuit appli-
cations. A DSU to modem interconnect diagram for this application is
shown in the appendix DSU to Modem Interconnect on page C-1.
The
E
XTERNAL
clock option is also recommended when the EIA-232 con-
nector is used for 56 kbps and 64 kbps applications. A special DSU cable
diagram for this application is shown in the appendix EIA-232 Connector
on page D-1. Using this option and special cable eliminates data errors
caused by excessive delays in the DTE transmit clock receiver and transmit
data driver.
1=NETW ORK OPT.
1=DTE RATE
2=DATA FORMAT
1=LOCAL 3=TX CLOCK 1=NORM AL
2=EXTERNAL
3=CONFIG 2=DTE OPTIONS 4=CS OPTIONS
2=REMOTE 5=CD OPTIONS
6=SR OPTIONS
3=TEST OPTIONS
4=DIAL OPTIONS
5=MANUAL COMMAND