Harris Intraplex STL-160 Series - Figure 2-10. Signal Flow after Primary Line Failure; Table 2-4. BER Threshold Detection Times

ACS-160 Series & STL-160 Series T1 Multiplexer Installation & Operation 2 – Functional Description
Version 2.11, August 2011
2-14 Harris Corporation
Intraplex Products
Figure 2-10. Signal Flow after Primary Line Failure
Table 2-4 shows the detection times for the selectable T1 line BER thresholds. Detection times are
different for E1 lines.
Table 2-4. BER Threshold Detection Times
Detection Time (Seconds) 10
-3
10
-4
10
-5
10
-6
Extended Superframe (ESF) 10s 10s 30s 105s
Superframe (SF) 30s N/A N/A N/A
The CM-5RB module monitors both the primary and the backup lines for these soft and hard failure
conditions. If line redundancy is enabled, the module compares the primary line is compared with the
backup line and decides which line to use. If the primary is Good, no switch is made. If the primary is
either Soft Fail or Hard Fail and the backup is Good, a switch is made. If the primary is Hard Fail and
the backup is Soft Fail, a switch is made. Tables 2-5 and 2-6 summarize these revertive/non-revertive
switching priorities.
Table 2-5. Failure Switching Precedence: Rev/Non-Rev Line Redundancy and Primary Line
Backup Line Status
Good Soft Hard
Primary Line Status
Good P P P
Soft B NC P
Hard B B NC
P = Primary Line is active
B = Backup Line is active
NC = No Change (current state)