Yealink SIP-T2 SERIES Administrator's Manual page 72

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
network.ip_address_mode =
The following specified configurations.

#Configure always forward feature.
forward.always.enable =
forward.always.target =
forward.always.on_code =
forward.always.off_code =
#Configure busy forward feature.
forward.busy.enable =
forward.busy.target =
forward.busy.on_code =
forward.busy.off_code =
#Configure no answer forward feature.
forward.no_answer.enable =
forward.no_answer.target =
forward.no_answer.timeout =
forward.no_answer.on_code =
forward.no_answer.off_code =
#Configure DND feature.
features.dnd.enable =
features.dnd.on_code =
features.dnd.off_code =
#Configure always forward feature for account X. (It is not applicable to SIP-T19(P)
E2 and CP860 IP phones. X stands for the serial number of account)
account.X.always_fwd.enable =
account.X.always_fwd.target =
account.X.always_fwd.on_code =
account.X.always_fwd.off_code =
#Configure busy forward feature for account X. (It is not applicable to SIP-T19(P) E2
and CP860 IP phones. X stands for the serial number of account)
account.X.busy_fwd.enable =
account.X.busy_fwd.target =
account.X.busy_fwd.on_code =
account.X.busy_fwd.off_code =
#Configure no answer forward feature for account X. (It is not applicable to
SIP-T19(P) E2 and CP860 IP phones. X stands for the serial number of account)
account.X.timeout_fwd.enable =
account.X.timeout_fwd.target =
50