Cisco 7800 Series Administration Manual page 278

Time
Parameter
Ignore DHCP Time Offset
Daylight Saving Time Rule
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
264
Cisco IP Phone Troubleshooting
Description
When used with some routers that have DHCP with
time offset values configured, the IP phone uses the
router settings and ignores the IP phone time zone
and offset settings. To ignore the router DHCP time
offset value, and use the local time zone and offset
settings, choose yes for this option. Choosing no
causes the IP phone to use the router's DHCP time
offset value.
Default: Yes.
Enter the rule for calculating daylight saving time; it
should include the start, end, and save values. This
rule is comprised of three fields. Each field is
separated by ; (a semicolon) as shown below. Optional
values inside [ ] (the brackets) are assumed to be 0 if
they are not specified. Midnight is represented by
0:0:0 of the given date.
This is the format of the rule: Start = <start-time>;
end=<end-time>; save = <save-time>.
The <start-time> and <end-time> values specify the
start and end dates and times of daylight saving time.
Each value is in this format: <month> /<day> /
<weekday>[/HH:[mm[:ss]]]
The <save-time> value is the number of hours,
minutes, and/or seconds to add to the current time
during daylight saving time. The <save-time> value
can be preceded by a negative (-) sign if subtraction
is desired instead of addition. The <save-time> value
is in this format: [/[+|-]HH:[mm[:ss]]]
The <month> value equals any value in the range 1-12
(January-December).
The <day> value equals [+|-] any value in the range
1-31.
If <day> is 1, it means the <weekday> on or before
the end of the month (in other words the last
occurrence of < weekday> in that month).