Yealink SIP-T2xP Auto Provisioning Manual page 229

Parameter
account.X.sip_server.Y.failback_timeout =
(SIP-T28P/T48G/T46G: X ranges from 1 to 6.
SIP-T26P/T22P/ T42G/T41P: X ranges from 1 to 3.
SIP-T21P/T20P: X ranges from 1 to 2.
SIP-T19P/CP860: X=1.
Y ranges from 1 to 2)
account.X.sip_server.Y.register_on_enable =
(SIP-T19P/CP860: X=1
SIP-T20P/T21P: X ranges from 1 to 2.
SIP-T22P/T26P/T41P/T42G: X ranges from 1 to 3.
SIP-T28P/T46G/T48G: X ranges from 1 to 6.
Y ranges from 1 to 2)
Permitted Values
registration requires renewal.
3-duration: the phone retries to use the
primary server after the timeout defined by
the parameter
"account.X.failback_timeout".
The default value is 0.
It configures the timeout (in seconds) for the
phone to retry to use the primary server
after failing over to the current working
server for account X when the parameter
Integer 0, from 60 to
"account.X.sip_server.Y.failback_mode" is
65535
set to 3 (duration).
If you set the parameter between 1 and 59,
the timeout will be 60 seconds.
The default value is 3600.
It enables or disables the phone to send
registration requests to the secondary
server for account X when encountering a
0 or 1
failover.
0-Disabled
1-Enabled
Descriptions
Appendix
Web Setting Path
219