Adtran 1200291L1 User Manual

Page of 192
Chapter 3. Configuration
61200659L1-1
MX2800 STS-1 User Manual
3-7
External Clock Configuration
PRI Ext. Clock and SEC Ext. Clock - When timing is set to 
external, these entries allow selection of the primary and secondary 
clock source. Any one of the 28 ports, so long as it is active, can be 
used. If the selected port does go into AIS or LOS, the selected 
clock becomes invalid. 
VT INTERFACE
The 
VT I
NTERFACE
 
menu (shown in Figure 3-4 on page 3-7) allows 
you to activate/deactivate individual T1s and E1s and to set their 
line coding, length, loopback detection, circuit protection, and line 
ID string. The T1/E1 code violation threshold is also configured 
through this menu. Configuration selections are described in the 
sections following Figure 3-4 on page 3-7.
Figure 3-4.  VT Interface Menu
A VT group can be divided into either three E1s or four T1s. Therefore, 
when dealing with an E1 configuration, some of the fields in the
 VT 
I
NTERFACE
 
menus do not apply (and therefore display 
N/A
).