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# Since in general, all NTP servers can be NTP clients and vice
# versa, all of the information in the /etc/inet/ntp.client file
# applies to NTP server setup as well. However, a certain kind
# NTP server, called a Stratum 1 server, has one or more devices
# designed to provide very accurate time to the server. These 
# devices are configured using the "server" keyword, just as the
# servers used by the client are, but instead of a hostname or 
# IP address, a format resembling an IP address is used. The first
# two octets of "127.127" are used to designate that this 
# line is referring to a clock and not an network NTP server. 
# The next octet is used to designate which type of device is used. 
# And the last octet is used to specify a unit number if more than
# one is used. Notice that the resulting number looks like the 
# localhost address, it is not the same. The real localhost
# address (127.0.0.1) does not have the second octet of 127 as
# the hardware clock designator does. 
#
# XType Device    RefID          Description
# -------------------------------------------------------
#  1    local     LCL            Undisciplined Local Clock
#  3    pst       WWV            PSTI/Traconex WWV/WWVH Receiver
#  4    wwvb      WWVB           Spectracom WWVB Receiver
#  5    true      TRUE           TrueTime GPS/GOES Receivers
#  6    irig      IRIG           IRIG Audio Decoder
#  7    chu       CHU            Scratchbuilt CHU Receiver
#  8    parse     ----           Generic Reference Clock Driver
#  9    mx4200    GPS            Magnavox MX4200 GPS Receiver
# 10    as2201    GPS            Austron 2201A GPS Receiver
# 11    arbiter   GPS            Arbiter 1088A/B GPS Receiver
# 12    tpro      IRIG           KSI/Odetics TPRO/S IRIG Interface
# 13    leitch    ATOM           Leitch CSD 5300 Master Clock Controller
# 17    datum     DATM           Datum Precision Time System
# 18    acts      ACTS           NIST Automated Computer Time Service
# 19    heath     WWV            Heath WWV/WWVH Receiver
# 20    nmea      GPS            Generic NMEA GPS Receiver
# 21    gpsvme                   GPS VME
# 22    atom      PPS            PPS Clock Discipline
# 26    hpgps     GPS            Hewlett Packard 58503A GPS Receiver
# 27    arc       MSFa           Arcron MSF Receiver
# 28    shm                      Shared memory driver
# 29    palisade                 Palisade
# 30    oncore                   Oncore
# 31    jupiter                  Jupiter GPS
# 32    chronolog                Chronolog
# 33    dumbclock                Dumbclock
# 34    ulink                    Ulink
# 35    pcf                      PCF
# 36    wwv                      WWV Audio
# 37    fg                       FG
# 38    hopfser                  HOPF Serial
# 39    hopfpci                  HOPF PCI
# 40    jjy                      JJY
# 41    tt560                    TT560
# 42    zyfer                    ZYFER
# 43    ripencc                  RIPEENCC
# 44    neoclock4x               NEOCLOCK 4X

# While all the current refclock drivers are configured and compiled,
# not all the actual hardware can be supported on all systems. The
# gpsvme driver can only be expected to work on systems with a VME 
# bus. The WWV audio driver can only be used on systems with audio
# input. 
#  
# In general, refclock type 1, the LOCAL clock is not necessary and
# should not be configured. It should only be used when either there
# is some other process being used to synchronize the clock, such as
# with hardware with vendor provided drivers, or when it is desired
# that a server without access to a real NTP time source needs to 
# act as a multicast or broadcast server. The LOCAL clock should not
# be configured as a "backup" to other external servers. 

# Some of the devices have tuning parameters, called "fudge" factors, 
# that can be set on the server line.  See the ntpd documentation.