AudioCodes Mediant 2000 User Manual page 318

19.1.1.2.1 Normal State
In normal state, the UAs register and operate directly with the external proxy.
Figure 19-3: SAS Redundant Mode in Normal State (Example)
19.1.1.2.2 Emergency State
If the UAs detect that their primary (external) proxy does not respond, they immediately
register to SAS and start routing calls to it.
Figure 19-4: SAS Redundant Mode in Emergency State (Example)
SIP User's Manual 318
Mediant 2000
Document #: LTRT-68814