Yealink SIP-T54S Administrator's Manual page 264

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860/CP920 IP Phones
first unused one (unused one means the DSS key is configured as N/A or Line). If a DSS key
is used, the IP phone will skip to the next unused DSS key.
The order of DSS key assigned automatically is Line Key->Ext Key.
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)
Example:
account.1.number_of_linekey = 1
Note: It works only if the value of the parameter "features.auto_linekeys.enable" is set to 1
(Enabled). To assign Ext Key, make sure the expansion module has been connected to the
phone in advance. It is not applicable to SIP-T19(P) E2/CP860/CP920 IP phones.
Web User Interface:
Account->Advanced->Number of line key
Phone User Interface:
None
phone_setting.call_appearance.transfer_via_new_linekey
Description:
Enables or disables the IP phone to transfer a call using a new line key when multiple line
keys are associated with an account.
0-Disabled
1-Enabled
If it is set to 0 (Disabled), the IP phone will transfer a call using the current line key.
If it is set to 1 (Enabled), the IP phone will transfer a call by automatically selecting a new
line key (the corresponding line key is not seized) instead of the current line key. If all line
keys are seized, the current line key will be used.
Note: The number of the line keys is determined by the value of the parameter
"account.X.number_of_linekey". The value configured by the parameter
"account.X.phone_setting.call_appearance.transfer_via_new_linekey" takes precedence over
that configured by this parameter. It is not applicable to SIP-T19(P) E2/CP860/CP920 IP
phones.
Web User Interface:
None
Phone User Interface:
238
Parameters
Permitted
Default
Values
0 or 1 1