Nortel Communication Server 1000S Installation And Configuration Manual page 64

Page 64 of 394 ISDN Primary Rate Interface equipment overview
Figure 18
Clock Controller primary and secondary tracking
Primary
clocking
source
Secondary
clocking
source
553-3001-201 Standard 2.00
REF 1
Primary
Reference
REF 2
REF 1
Secondary
Reference
REF 2
Free run (non-tracking) mode
The clock synchronization of the system can operate in free-run mode if:
• no loop is defined as the primary or secondary clock reference,
• the primary and secondary references are disabled, or
• the primary and secondary references are in local (near end) alarm
September 2004
Primary
Primary
Secondary
Secondary
Clock
Controller 0
J1
J2
J3
Clock Controller
Backup
Clock
Controller 1
J1
J2
J3