Instruction Manual

Hot-Standby EXB / Network Manager
Software Manual Network Manager
CTI Products, Inc. Program Operation
35
68-11707-100
6.8.5 Main (Central) EXB Failed
Figure 31 Main (Central) EXB Failed
Since the loop is not complete, the Standby EXB turns on its network switch to
pass traffic over the Standby WAN line.
In this condition, the program can talk to the units as follows:
EXB Forward
(Clockwise)
Reverse
(Counter-Clockwise)
Main (Central) No No
Standby (Central) No Yes
Remote Standby No Yes
Remote Main No Yes
Based upon this, the program determines that the Central Main EXB unit is bad.
Other possible causes for this display could be:
1. No power to the Central Main EXB module.
2. A bad Main WAN line AND a bad Central tie line.
(Highly unlikely that two failures have occurred.)
However, the program flags these lines as questionable since it cannot
determine that they are good.