4RF Aprisa XE User Manual page 80

78 | Configuring the Terminal
To select the interface port for the external clock source (external clock source only):
Select the traffic interface ports nominated as Primary External Clock or Secondary External Clock
sources.
The failure of both External Clock sources results in a major alarm.
To manually override the automatic clock source selection (external clock source only):
Select either Switch to Primary or Switch to Secondary from the drop-down list, and click Apply.
Aprisa XE User Manual