User's Manual

455U-D Radio Modem Module User Manual
Page 64 © Jan 2008
• Use the configuration port to force a changeover from secondary active to primary
active, or from primary active to secondary active.
- to force a changeover from primary to secondary, use command AT#O5.
- to force a changeover from secondary to primary, use the command AT#O6.
- the status of the Dual Redundant system is displayed in register S33.
The following image shows the states of the dual redundant system and the relationship to the
AT#O commands, and S-registers S33 and S11.
Start
Get Control
S33=2
Active
S33=2
Active No
Secondary
S33=4
Standby
S33=5
Secondary Active
Fault cleared
Secondary Responding
Secondary Not Responding
E455U-D Dual Redundant
Control - Primary
AT#O3
E455U-D Dual Redundant
Control - Secondary
AT#O4
Start
Standby
S33=6
Active
S33=3
Primary Inactive
Activity From Primary
Give Control
S33=6
Primary Inactive
Primary Active
Secondary Inactive
Secondary Inactive
Force
Changeover
S33=6
Primary Inactive after timeout
(S11)
AT#O6
Primary Active
Forced
Standby
S33=5
Fault
Timeout (S11)
AT#O5