Symmetricom TimeSource 3000 Manual page 3

Acronyms and Abbreviations
AIS alarm indication signal
E1 digital transmission (2.048 Mb/s)
ESD electrostatic discharge
ESF extended superframe
GPS Global Positioning System
LOS loss of signal
MDEV mean time deviation
pps pulse per second
PRS primary reference source
RO remote oscillator
RU rack unit (1.75 in.)
SSM synchronization status messaging
T1 digital transmission (1.544 Mb/s)
TDEV time deviation
TOD time of day
UTC Universal Coordinated Time