Yealink SIP-T54S Administrator's Manual page 786

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860/CP920 IP Phones
X ranges from 1 to 2 (for SIP-T21(P) E2)
X is equal to 1 (for SIP-T19(P) E2/CP860/CP920)
Note: DNSTTL, Registration and duration mode can only be processed when the IP phone is
idle (that is, no incoming/outbound calls, no active calls or meetings, etc.).
Web User Interface:
None
Phone User Interface:
None
account.X.sip_server.Y.failback_timeout
(X ranges from 1 to 16, Y ranges from 1 to 2)
Description:
Configures the timeout (in seconds) for the phone to retry to send requests to the primary
server after failing over to the current working server for account X.
If you set the parameter to 0, the IP phone will not send requests to the primary server until
a failover event occurs with the current working server.
If you set the parameter from 1 to 59, the timeout will be 60 seconds.
X ranges from 1 to 16 (for SIP-T54S/T48G/T48S/T46G/T46S/T29G)
X ranges from 1 to 12 (for SIP-T52S/T42G/T42S)
X ranges from 1 to 6 (for SIP-T41P/T41S/T27P/T27G)
X ranges from 1 to 3 (for SIP-T40P/T40G/T23P/T23G)
X ranges from 1 to 2 (for SIP-T21(P) E2)
X is equal to 1 (for SIP-T19(P) E2/CP860/CP920)
Note: It works only if the value of the parameter "account.X.sip_server.Y.failback_mode" is
set to 3 (duration).
Web User Interface:
None
Phone User Interface:
None
account.X.sip_server.Y.failback_subscribe.enable
Description:
Enables or disables the IP phone to retry to re-subscribe after registering to the secondary
server with different IP address for account X when encountering a failover.
0-Disabled
1-Enabled
760
Parameters Permitted Values Default
0, Integer from
3600
60 to 65535
0 or 1 0