Specifications

Defining a Custom Time Zone Reference Manual (MGCP/NCS Version)
Mediatrix 4100
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Defining a Custom Time Zone
When starting, the Mediatrix 4100 queries a NTP or SNTP server to receive time information. It receives the
information in Greenwich Mean Time (GMT) format (also known as Universal Time Coordinated - UTC), so it
needs to convert this GMT time into the proper time zone. To do this, the Mediatrix 4100 offers time zone
configuration with daylight saving settings.
 To define a custom time zone:
1. In the sntpMIB, enter a valid POSIX (Portable Operating System Interface) string in the
sntpTimeZoneString variable as defined in the <bootp-dhcp-option-88.txt> Internet draft.
The format of the string is validated upon entry. Invalid entries are refused. The default value is:
EST5DST4,M4.1.0/02:00:00,M10.5.0/02:00:00
A POSIX string is a set of standard operating system interfaces based on the UNIX operating
system. The format of the IEEE 1003.1 POSIX string is defined in the <bootp-dhcp-option-88.txt>
Internet draft as:
STDOFFSET[DST[OFFSET],[START[/TIME],END[/TIME]]]
Refer to the following sub-sections for explanations on each part of the string.
STD / DST
Three or more characters for the standard (STD) or alternative daylight saving time (DST) time zone. Only STD
is mandatory. If DST is not supplied, the daylight saving time does not apply. Lower and upper case letters are
allowed. All characters are allowed except digits, leading colon (:), comma (,), minus (-), plus (+), and ASCII
NUL.
OFFSET
Difference between the GMT time and the local time. The offset has the format h[h][:m[m][:s[s]]]. If no offset is
supplied for DST, the alternative time is assumed to be one hour ahead of standard time. One or more digits
can be used; the value is always interpreted as a decimal number.
The hour value must be between 0 and 24. The minutes and seconds values, if present, must be between 0
and 59. If preceded by a minus sign (-), the time zone is east of the prime meridian, otherwise it is west, which
can be indicated by the preceding plus sign (+). For example, New York time is GMT 5.
START / END
Indicates when to change to and return from the daylight saving time. The START argument is the date when
the change from the standard to the daylight save time occurs; END is the date for changing back. If START
and END are not specified, the default is the US Daylight saving time start and end dates. The format for start
and end must be one of the following:
 n where n is the number of days since the start of the year from 0 to 365. It must contain the
leap year day if the current year is a leap year. With this format, you are responsible to
determine all the leap year details.
 Jn where n is the Julian day number of the year from 1 to 365. Leap days are not counted. That
is, in all years – including leap years – February 28 is day 59 and March 1 is day 60. It is
impossible to refer to the occasional February 29 explicitly. The TIME parameter has the same
format as OFFSET but there can be no leading minus (-) or plus (+) sign. If TIME is not
specified, the default is 02:00:00.
 Mx[x].y.z where x is the month, y is a week count (in which the z day exists) and z is the day
of the week starting at 0 (Sunday). As an example:
M10.4.0
is the fourth Sunday of October. It does not matter if the Sunday is in the 4th or 5th week.
M10.5.0
Standards Supported bootp-dhcp-option-88.txt Internet draft