Yealink SIP-T2 SERIES Administrator's Manual page 212

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
Parameters
local_time.end_time
Description:
Configures the end time of the DST.
Value formats are:
Month/Day/Hour (for DST by Date)

Month/Week of Month/Day of Week/Hour of Day (for DST by Week)

If "local_time.dst_time_type" is set to 0 (DST by Date), use the mapping:
Month: 1=January, 2=February,..., 12=December
Day: 1=the first day in a month,..., 31= the last day in a month
Hour: 0=0am, 1=1am,..., 23=11pm
If "local_time.dst_time_type" is set to 1 (DST by Week), use the mapping:
Month: 1=January, 2=February,..., 12=December
Week of Month: 1=the first week in a month,..., 5=the last week in a month
Day of Week: 1=Monday, 2=Tuesday,..., 7=Sunday
Hour of Day: 0=0am, 1=1am,..., 23=11pm
Note: It works only if the value of the parameter "local_time.summer_time" is set to 1
(Enabled).
Web User Interface:
Settings->Time & Date->End Date
Phone User Interface:
None
local_time.offset_time
Description:
Configures the offset time (in minutes) of DST.
Note: It works only if the value of the parameter "local_time.summer_time" is set to 1
(Enabled).
Web User Interface:
Settings->Time & Date->Offset(minutes)
Phone User Interface:
None
To configure the DST via web user interface:
Click on Settings->Time & Date.
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Permitted Values
Time
Integer from -300 to 300
Default
12/31/23
Blank