Yealink W53P

Account Settings
115
The incoming line for handset 6 is line 6.
The incoming line for handset 7 is line 7.
The incoming line for handset 8 is line 8.
Web UI Account->Number Assignment->Outgoing lines
Parameter
handset.X.dial_out_default_line
[1]
<y0000000000xx>.cfg
Description It configures the default line to place outgoing calls for the handset.
Permitted Values Integer from 1 to 8
Default
The default outgoing line for handset 1 is line 1.
The default outgoing line for handset 2 is 2.
The default outgoing line for handset 3 is 3.
The default outgoing line for handset 4 is 4.
The default outgoing line for handset 5 is 5.
The default outgoing line for handset 6 is 6.
The default outgoing line for handset 7 is 7.
The default outgoing line for handset 8 is 8.
Web UI Account->Number Assignment->Outgoing lines->Default
Handset UI OK->Settings->Telephony->Default Line
[1]
X is the handset ID. X=1-8.