Elproma NTS-4000 User manual

ELPROMA Electronics Network Time Service
USER MANUAL
GPS Network Time Server
NTS–4000 OCXO
ELPROMA
l st upd te
J nu ry 22, 2008
01/22/2008 Page 1/41

ELPROMA Electronics Network Time Service
Contents
SAFETY INSTRUCTIONS !................................................................................3
1. Introd ction....................................................................................................................................4
2.Hardware.........................................................................................................................................5
3.Mo nting GPS antenna...................................................................................................................7
4.Powering p NTS–4000................................................................................................................10
5.Basic device config ration............................................................................................................11
6.Error messages..............................................................................................................................12
7.NTP – Network Time Protocol.....................................................................................................13
8.NTP on Time Fail re Tolerance Network.....................................................................................16
9.NTS–4000 software Set p............................................................................................................17
10.Sec rity and NTP a thentication mode......................................................................................30
11.NTPq client diagnostic tility.....................................................................................................32
12.Installing NTP client software....................................................................................................34
12.1.Windows 95/98/Me (SNTP client)..........................................................................................35
12.2.Windows NT/2K/XP/2003/Vista (NTP Client).......................................................................36
12.3.UNIX family systems...............................................................................................................37
13.Technical specification:...............................................................................................................39
13.1.SYSTEM..................................................................................................................................39
13.2.HARDWARE...........................................................................................................................39
13.3.CASE........................................................................................................................................40
13.4.GPS...........................................................................................................................................40
13.5.POWER....................................................................................................................................40
13.6.ACCURACY...........................................................................................................................40
13.7.OTHER....................................................................................................................................41
•List of figures
Fig re 1: NTS-4000 Network Time Server........................................................................................4
Fig re 2: Front panel of NTS–4000....................................................................................................5
Fig re 3: Back panel of NTS-4000.....................................................................................................5
Fig re 4: GPS world wide time propagation......................................................................................7
Fig re 5: GPS antenna installation.....................................................................................................7
Fig re 6: NTS–4000 GPS antenna box..............................................................................................8
Fig re 7: NTS–4000 GPS antenna box – inferior view.....................................................................8
Fig re 8: NTS–4000 Front panel keyboard......................................................................................11
Fig re 9: Time Adj stments Using Stepping and Slewing...............................................................13
Fig re 10: Strata tree.........................................................................................................................14
Fig re 11: Example of NTP strat m config ration in local LAN peer............................................15
Fig re 12: Main men .......................................................................................................................18
Fig re 13: Entering IP address..........................................................................................................19
Fig re 14: Entering MASK address..................................................................................................19
Fig re 15: Entering DEFAULT GATEWAY address........................................................................20
Fig re 16: Entering IPv6 address......................................................................................................20
Fig re 17: Enabling/Disabling remote access to NTS–4000...........................................................21
Fig re 18: Enabling SYSLOG..........................................................................................................22
Fig re 19: Enabling SNMP MIBv2 service......................................................................................23
Fig re 20: Defining list of NTP back p servers (Strat m 1)............................................................24
Fig re 21: Setting RTC date..............................................................................................................25
Fig re 22: Setting RTC time.............................................................................................................26
Fig re 23: A thentication tilities.....................................................................................................27
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ELPROMA Electronics Network Time Service
Fig re 24: Other f nctions................................................................................................................28
Fig re 25: Broadcast NTP mode.......................................................................................................30
Fig re 26: MD5 keyid for broadcast mode.......................................................................................31
Fig re 27: NTPq diagnostic for Windows NT/2000/XP..................................................................32
Fig re 28: SNTP client for Windows 95/98/Me...............................................................................35
Fig re 29: NTP client set p - first IP address for local clock...........................................................36
Fig re 30: File ntp.conf.....................................................................................................................36
SAFETY INSTRUCTIONS !
This are the important Safety Instr ctions that sho ld be followed d ring installation
and maintenance of the Elproma NTS-4000 time servers prod ct.
IMPORTANT NOTE !
This equipment contains hazardous voltages. o not handle any metallic part until
the power has been disconnected. o not assemble, disassemble set when the power
is ON. Making wiring and touching cables is strongly prohibited when power is
ON. Please refer to your RACK’19 safety instruction to learn more about
connecting power to equipment. The NTS-protection system requires PE line to be
connected into RACK’19 din rails.
Elproma safety advices:
1. Do not work alone under hazardous conditions.
2. High short circuit current trough conductive materials
can cause severe burns.
3. Check that the power cord s), plug s), and sockets are in good conditions.
4. Use qualified service personnel to install permanently wired equipment.
5. Do not handle any metallic part before the power has been disconnected.
6. Take care your power lines and rack'19 frame are properly grounded.
Elproma Electronics Team
01/22/2008 Page 3/41

ELPROMA Electronics Network Time Service
1. Introduction
The NTS–4000 Network Time Server provides a high precision time directly to TCP/IP
networks sing NTP (Network Time Protocol RFC 1305) and SNTP (Simple Network Time
Protocol RFC 2030). It synchronizes time of any NTP or SNTP clients r nning on remote PC’s.
It s pports majority of c rrent pop lar operating systems incl ding: Windows, Mac OS/X, Lin x,
Free BSD, HP-UX, IBM AIX, IBM AS/400, SUN Solaris and many other UNIX family systems.
It can synchronize sim ltaneo sly over 10,000 servers, workstations , ro ters and other devices
s pporting NTP or SNTP clients.
NTS-4000 provides acc rate time via 2xLAN (10/100Mbps Ethernet) as well as via vario s of
I/O sync standards incl ding: IRIG-B*, 1PPS.
Figure 1: NTS-4000 Network Time Server
The acc rate UTC time is powered by n mero s time so rces incl ding: do ble (A/B)
red ndant GPS antenna system, external 1PPS inp t or external IRIG-B*. Unit incl des internal
high precision OCXO oscillator for time back p in case of GPS receiving problems or fail re.
Special DCF77* RF-AM* time pattern s pport is available for Central E rope and Germany.
NTS–4000 distrib tes UTC reference time to 2 isolated (not ro ted) s b-networks:
LAN1, LAN2. All time and satellite informations can be traced on front panel 2x20 characters
LCD display. More detailed statistic is available by remote NTP software tilities (”ntpq”,
”ntpdc”), set p tility or other software interfaces like: WWW, TELNET, SSH, SNMP.
NTS–4000 can operate in standard or special NTP a thentication mode protected by MD5
algorithms. Unit s pports broadcast, manycast, m lticast and client/server NTP modes.
Special fast sync startup mode of NTP has been implemented to red ce nsynchronized
time after powering p prod cts which has no battery powered p RTC clocks.
NTS–4000 is ready to work with any SYSLOG or SNMP (MIB2) server. It let friendly
warn on any nexpected sit ation that may happen in yo r time synchronized network.
NTS-4000 is designed to operate witho t ventilators and fans. Metal ho sing is an
important part of NTS–4000 nat ral cooling system designed in s ch way that nit can be located
in the neighbo rhood of any device working inside rack19 mo nt frame.
A tr e novelty is an option to create cascade NTS servers where one can sim late an
antenna for the other. This f nctionality enables time synchronization of sec red LANs with
official time from NTP servers available p blicly on line in Internet.
* - special feature option required to be purchased separately)
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ELPROMA Electronics Network Time Service
2.Hardware
The NTS–4000 time server set incl des:
•NTP time server nit (Rack'19/1U) with b ilt in OCXO oscillator .....................pcs 1
•External GPS antenna box Channel A) ................................................................pcs 1
•GPS antenna box mo nting handler .....................................................................pcs 1
•Ethernet cable (2m) ...............................................................................................pcs 2
•Power cable (230V AC) ..........................................................................................pcs 1
•Set of RJ45 connectors /to be cramped on the end of antenna cable/ .....................pcs 4
•CD with Windows software and PDF man al.........................................................pcs 1
extra options to be ordered separately /not incl ded in set/:
•Antenna cable (UTP or STP Cat. 5)
•External 2nd GPS antenna box Channel B)
•E ropean RF-AM DCF77 receiver mod les (for both channels A & B)
•IRIG-B s pport firmware pgrade
•1PPS coaxial cable (50Ohm for external 1PPS synchronization)
•NTS-protect – lighting system
The 2x20 characters LCD display shows: GPS stat s, local or UTC time stamp
information, GPS antenna position and vario s of system parameters like: internal temperat re etc.
The device comes with 6-key keyboard for: q ick IP device config ration, firmware rev. info,
factory defa lt restoring etc. The RS232 and 2x USB are preserved for f t re f nctionality and
service p rposes. LAN2 connector contains 2 LEDs: green - indicates cable connection, yellow -
flashes while data is being transmitted. Each pl gging/ npl gging of Ethernet cable will be
indicated on LCD display by reviewing TCP/IP config ration for specific LAN interface.
On the back panel there is a power connection 110/230V AC (50Hz), LAN1, 2xGPS
antenna connectors (A/B) and vario s I/O time interfaces. Below table describes connectors and
related into it f nction:
01/22/2008 Page 5/41
Figure 2: Front panel of NTS–4000
Figure 3: Back panel of NTS-4000

ELPROMA Electronics Network Time Service
Name Connector Standard P rpose Availability
Antenna (A) RJ-45 RS-485 Antenna connector (main antenna) +
Antenna (B) RJ-45 RS-485 Antenna connector (back p antenna) +
IRIG-B IN* BNC IRIG-B IRIG-B so rce signal (optionally) +
IRIG-OUT* BNC IRIG-B IRIG-B o tp t signal (optionally) +
10 MHz BNC 10MHz 10 MHz o tp t reference signal x
1 PPS IN BNC 1pps 1 PPS (p lse per second) so rce signal +
1 PPS OUT BNC 1pps 1 PPS (p lse per second) o tp t signal x
TIMER IN DSUB9 RS-232 2xPPS (p le per second) inp t signal x
TIMER OUT DSUB9 Vario s Extra feat re (not available yet) x
LAN1 RJ-45 TCP/IP Local Area Network interface (back panel) +
LAN2 RJ-45 TCP/IP Local Area Network interface (front panel) +
RS-232 DSUB9 RS-232 For technical and service p rpose +
USB KUSB USB For technical and service p rpose +
There are 2 LED (red, green) on the back panel of NTS-4000 to indicate GPS, OCXO 1PPS
synchronization. The following nit stat s is reported on LED's:
GREEN LED STATUS
OFF NTP daemon not started
ON NTP daemon started
BLINKS synchronized to OCXO
RED LED STATUS
OFF No GPS signal
ON synchronized to GPS (NMEA)
BLINKS synchronized to GPS (1PPS)
01/22/2008 Page 6/41
* - special feature option required to be purchased separately)
x – absolute for this model
D al Antenna A/B system,
Each antenna Channel (A/B) can operate as INPUT or OUTPUT (GPS NMEA mode). Antenna inp t
mode can s pport sim ltaneo sly GPS + DCF77* receivers. Antenna OUTPUT mode s pports only
GPS (NMEA) em lation + 1PPS s pport. Elproma offers additional hardware for NTP time servers.
New generation time reference pattern can be sim ltaneo sly drown from GPS L1/L2, SBAS, EGNOS,
WAAS, GLONASS, and tomorrow from GELILEO too.

ELPROMA Electronics Network Time Service
3.Mounting GPS antenna
The GPS satellite time receiver has been designed to provide extremely precise time. High
precision available 24 ho rs a day aro nd the whole world. The Global Positioning System (GPS)
is a satellite-based radio-positioning, navigation, and time-transfer system. The so rce of time is
based on cesi m atomic clocks. Time is represented as UTC.
The GPS satellites are not stationary b t circle ro nd the globe in a period of approx. abo t
12 ho rs. They can only be received if there is no b ilding in the line of sight from the antenna to
the satellite, so the antenna nit m st be installed in a location from which as m ch of the sky as
possible can be seen.
01/22/2008 Page 7/41
Figure 5: GPS antenna installation
Figure 4: GPS world wide time propagation

ELPROMA Electronics Network Time Service
The hardware of the GPS antenna contains in one box. In a box are placed GPS receiver,
freq ency converter and basic over-voltage protection. Box is water resistant (IP67) therefore it
sho ld stay over water level d ring rain.
The metal handler sho ld be mo nted on top of b ilding. Please select location of GPS
antenna on way it work will be not dist rbed by any other radio-transmitter or antennas. We
advice to keep min. distance of 5m from other electronic devices as GSM/UMTS transceivers,
radars, telecoms eq ipment, air conditions etc. Yo r GPS box antenna sho ld be mo nted solid to
avoid strong winds and other bad weather conditions. Water, salt and snow conditions are
acceptable nder condition the box remind over water level (IP67).
For s rge and over voltage protection please refer to NTS-protect*** man al /available
separately/. This mod le incl des special lightning protectors preventing NTS-4000 server from
direct and indirect effects of atmospheric discharges and related over voltage defects.
The constr ction of NTS-protect is based pon the r le of voltage compensation in accordance
with PN – IEC 61024-1 standard reg lations. It stim lates pholding safe levels of over voltage
that will not damage the ins lation in all protected electrical circ its of the NTS-4000 server.
*** NTS-protect is available as separate prod ct.
01/22/2008 Page 8/41
Figure 7: NTS–4000 GPS
antenna box – interior view
Figure 6: NTS–4000 GPS
antenna box

ELPROMA Electronics Network Time Service
For connecting antenna (GPS or DPS + DCF77) box we recommend sage of UTP or STP
CAT5 cables (for external environment. se) with standard RJ-45 connector termination (both
sides) with standard T568B cond ctors assignment. Cable sho ld be leaded into antenna box
thro gh cable gland. Please se standard Ethernet cramping tooling (not incl ded to NTS-4000
set) to mo nt antenna cable connection.
GPS antenna conductors assignment
PIN
RJ45
GPS Signal UTP Cat 5 cable
1 PPS+ White/Orange
2 PPS- Orange
3 TR+ White/Green
4 DCF- Bl e
5 DCF+ White/Bl e
6 TR- Green
7 +VCC White/Brown
8 -0V Brown
GND GND Not sed
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ELPROMA Electronics Network Time Service
4.Powering up NTS 4000
If both the antenna (GPS, DCF77 or GPS+DCF77) and the power s pply have been
connected the system is ready to operate. Yo can t rn on a power switch located on the back
panel of NTS-4000.
Typically, time d ration of NTS-4000 power- p is eno gh for the antenna (GPS) box
receiver to start to operate with the req ired acc racy. If the GPS receiver finds valid almanac and
ephemeris data in its battery b rred memory (and the receiver position has not changed
significantly since its last operation) the receiver can find o t which satellites are in its view at that
now. Fo r satellites needs to be fo nd to synchronize and generate o tp t p lses.
If the receiver position has changed by some kilometers since the last operation, the
satellites real elevation and Doppler might not match the val es expected by the receiver th s
forcing the receiver to start scanning for satellites. When the receiver has fo nd fo r satellites in
its view it can pdate its new position and switch to Normal Operation. If the almanac has been
lost beca se of battery disconnection the receiver has to scan for a satellite and read in the c rrent
almanacs. When antenna has clear view of the sky it takes p to 30 min tes ntil the new almanac
is completed and the system starts to operate. For this time NTS-4000 will operate from it's
internal q artz time clocks.
After starting p the system the network f nction is initiated and the program for
comm nication between GPS and NTP becomes active. The following screen appear on LCD
display while starting.
NTS–4000 LCD display
From the left side there are: date and time, error stat s, UTC time, n mber of satellites
reached per total amo nt of visible satellites.
It is possible to set p m ch shorter start p time of NTP (abo t 1 min te) by selecting a
special “Fast” option in “Misc” men of SETUP. This can be helpf l for environments with a high
risk of nexpected power down. Using this option res lts in less acc rate (approx 1s error of time
information provided by NTP service d ring first 3-4 min tes of operation).
01/22/2008 Page 10/41
17-02-2006 Err sync
18:02:21 sat A= 5/12
Important Note!
The NTP starts max. 5 minutes after powering ON it does not
matter what status of time sources actually are if they are
connected, GPS is synchronized etc.). During this approx. 5
minutes long start time NTP searches for best available
source and builds statistic information in order to be able to
detect corrupted sources false tickers in NTP notification).
After approx. 5 minutes period NTP selects best source as
currently used and other sources also correct but less
accurate) as backup sources.

ELPROMA Electronics Network Time Service
5.Basic device configuration
After first power p, at least basic config ration sho ld be performed in order to set p
proper interfaces IP config ration. This can be done sing front panel keyboard.
To enter set p mode press and hold “OK” b tton. Now yo can config re LAN1 interface.
Following screens will appear on LCD:
LAN1 IP address config ration
LAN1 IP address mask config ration
LAN1 defa lt gateway config ration
To navigate thro gh digits se “←” and “→” keys. To increase val es se “↑” key, to
decrease se “↓” key. One can instantly clear c rrently edited parameter to zeros by pressing “C”
key. Pressing “OK” b tton switches to next parameter. After config ring LAN1 interface, LAN2
interface screens are shown. After config ring all parameters following screen is shown:
Config ration confirmation screen
In order to save config ration press “OK” b tton. NTS-4000 will reboot and operate with
new setting. If yo want to keep old config ration simply press “C” b tton and no changes will be
made. In order to exit from config ration mode j st press “OK” b tton as many times as needed to
obtain confirmation screen and then press “C” b tton. This operation m st be done with ca tion
in order to avoid saving bad settings.
This method allows only base LAN interfaces config ration. In order to change other
NTS-4000 settings console config ration option is available.
01/22/2008 Page 11/41
LAN1 IP address:
192.168.000.210
LAN1 netmask:
255.255.255.000
LAN1 ateway:
192.168.000.001
Are you sure?
[OK]-Yes [Cancel]-No
Figure 8: NTS–4000 Front panel
keyboard

ELPROMA Electronics Network Time Service
6.Error messages
If no antennas are c rrently connected to NTS-4000 device following error screen will be
shown:
Error: all antennas disconnected
The NTS–4000 req ires minim m 5 satellites to be reached contin o sly in order to get
time from GPS properly. This fig re is not constant and it is changing in non-reg lar way.
If satellite comm nication is lost the following message appears:
Error: missing GPS satellites
Error: bad GPS geometry
This req ires finding better GPS antenna location otherwise NTS–4000 cannot obtain time
information from GPS antenna. The nit will still work properly b t will provide time according
to RTC which time need to be set p man ally thro gh console and its acc racy is poor.
The LCD shows only a stat s of the GPS antennas. It does not show stat s of the other time
so rces as I/O time interfaces (1PPS, IRIG-B etc.). However other time so rces can be monitored
and traced by a remote software tility ntpq (cl num command of ntpq tility, where num
can be g essed from as command).
There another error message “Err sync” is possible to be displayed. It indicates that internal
phase/freq ency loop is not yet locked or temporary not working, beca se of 1PPS jitter or too
m ch offset from GPS time.
Error: GPS is not in sync
Last possible error message is “Error call service” message. It means that device is not
operating properly (message will show p approx. 30 sec after rebooting). Contact service in this
sit ation for f rther instr ctions.
Error: Device o t of order
Before yo learn how to set p NTS–4000, yo also sho ld read abo t NTP itself.
01/22/2008 Page 12/41
17-02-2006 Err sats
18:02:21 ANT ERROR
17-02-2006 Err sats
18:02:21 sat A= 1/12
17-02-2006 Err sync
18:02:21 sat A= 5/12
Error call service
[phone]
17-02-2006 Err sats
18:02:21 sat A= 1/12

ELPROMA Electronics Network Time Service
7.NTP Network Time Protocol
NTP is a common method for time synchronization over networks. The NTP is m ch
different from any of known other comm nication protocols. It is beca se NTP does not base on
the principles of synchronizing machines to each other. It is based on the principles of having all
machines get as close as possible to the UTC time provided by NTS–4000. How it works?
NTS–4000 forms a statistic of delays and other data necessary to calc late local client RTC
time offset. Knowing time difference the adj stment of the own RTC clock can be preceded
individ ally by each NTP client.
NTP works on a hierarchical model in which a small n mber of servers gives time to a
large n mber of clients. The clients on each level, or strat m, are in t rn, potential servers to an
even larger n mber of clients on a higher n mbered strat m. Strat m n mbers increase from the
primary (strat m 1) servers to the lowest n mbered strata at the bottom of the tree (strat m 15).
Clients can se time information from m ltiple servers to determine a tomatically the best so rce
of time and prevent wrong time so rces from corr pting their own time.
In most cases it will take several min tes (or even ho rs) to adj st a system time to the
ltimate degree of acc racy. There are several reasons for this. The most important one is that
NTP averages the res lts of several time exchanges in order to red ce the effects of variable
latency. This may take several min tes for NTP to even reach consens s on what the average
latency is. Generally it happens in abo t 5-10 min tes. In addition, it often takes several
adj stments for NTP to reach a synchronization. The res lt is that sers sho ld not expect NTP to
immediately synchronize two clocks. The ntpdate command can be sed if an instant
synchronization is needed.
The peers command can be sed in ntpq to determine whenever the synchronization has
been achieved. When a client has synchronized, the synchronization server is listed with an
asterisk in front of it.
To allow clocks to q ickly achieve the high acc racy, yet avoid overshooting the time with
large time adj stments, NTP ses a system where large adj stments occ r q ickly and small
adj stments occ r over time. For small time differences (less than 128 ms), NTP ses a grad al
adj stment. This is called slewing. For larger time differences, the adj stment is immediate. This
is called stepping.
D e to NTP specification NTS–4000 is visible over network as a peer. Single peer can
contain more than single timeservers in order of a hierarchy called strat m. The top of the strat m
tree is preserved for radio-controlled timeservers s ch as NTS–4000. Therefore NTS–4000 will
always be yo r stratum1 timeserver. Other connected comp ters can also work in timeserver mode
01/22/2008 Page 13/41
Figure 9: Time Adjustments Using Stepping and Slewing

ELPROMA Electronics Network Time Service
b t they will be set down to stratum2 or even m ch below.
The NTS–4000 time server s pports m ltiple so rce of time (depends of config ration).
Each so rce is Strat m 0 (except RTC working on Strat m 5 level). The NTS–4000 incl des
following time so rces:
Internal Time Patterns #STRATA
•2x 1PPS GPS (p lse per second) signal PLL/FLL locked STRATUM-0
•2x GPS (NMEA) 1.5GHz radio signal (worldwide) STRATUM-0
•2x DCF77 55.7kHz radio signal (Central E rope - Germany only)* STRATUM-0
•1x IRIG-B signal (external connector) STRATUM-0
•1x PPS_IN signal (external connector e.g. to cesi m 5051A) STRATUM-0
•1x OCXO (1PPS) internal q artz oscillator for GPS fail re STRATUM-0
•1x RTC internal q artz clock systems for back p. STRATUM-5
* - special feature option required to be purchased separately)
A high precision synchronization is chosen by NTP a tomatically. The NTP always selects
best available so rce of time. Selection is based on several time references like: strat m level,
availability of timeserver, network delay, time difference, internal jitter factor, etc.
NTP clients of NTS–4000 are referred to be a Stratum 2 clients. If they serve time to other
clients, they are also referred as Stratum 2 servers. The maxim m NTP strat m n mber for a
client is 15.
NTP ses the UDP protocol on port 123 to comm nicate between clients and servers.
Attempts are performed at designated intervals ntil the server responds. All NTS-4000 antennas
works red ndantly and they are NTP visible as Strat m 0.
The interval depends on a n mber of factors and ranges from abo t once a min te to once
every 17 min tes. Using UDP prevents retries from sing p network bandwidth if a time server
with a large n mber of clients goes down. The bandwidth req irements for NTP are also minimal.
Unencrypted NTP Ethernet packets are 90 bytes long (76 bytes long at the IP layer). A
01/22/2008 Page 14/41
Figure 10: Strata tree

ELPROMA Electronics Network Time Service
broadcast server sends o t a packet abo t every 64 seconds. A nonbroadcast client/server req ires
2 packets per transaction. When synchronization starts, transactions occ r abo t once per min te,
increasing grad ally to once per 17 min tes nder normal conditions. Poorly synchronized clients
will tend to poll more often than those well synchronized clients. Starting from NTP version 4
implementations, the minim m and maxim m intervals can be extended beyond these limits, if
necessary.
01/22/2008 Page 15/41
Figure 11: Example of NTP stratum configuration in local LAN peer

ELPROMA Electronics Network Time Service
8.NTP on Time Failure Tolerance Network
M ltiple time so rce system of NTS–4000 already improves safety beca se it protects
sit ation when a single so rce co ld fail. B t it is also possible to se several NTS–4000 nits
sim ltaneo sly to improve stability of the time synchronization. In this case all NTS–4000 nits
wo ld work independently and f lly red ndant or in a pool mode. If one server fails another are
still working and NTP swaps to the new existing so rce a tomatically.
There is act ally one more possibility of NTS–4000. Yo can define p to 3 NTP back p
servers for single NTS–4000 nit. In this mode NTS–4000 reminds Strat m 1 as long as one of
time so rces works fine. B t in case of no time so rce availability NTS–4000 checks back p
servers list. If NTP accepts any of them, the NTS–4000 red ces its strat m to N-1 (where N is a
Strat m of approved server taken o t of the back p list). We advice to specify only Strat m 1
servers on NTS–4000 back p list. This does not let red ce NTS–4000 Strat m below 2.
Every NTS–4000 incl des b ilt-in OCXO q artz generator and RTC clock as back p
time so rce when GPS (DCF77) and/or OCXO failed. Us ally NTP will always choose OCXO (if
previo sly synchronized to GPS). The RTC is the last possible choice for NTP if no other time
patterns can be received. Since RTC Strata is 5, in case of sing it NTS–4000 Strata will be
red ced to 6.
A tr e novelty is an option to create cascade NTS servers where one can sim late an
antenna for the other. This f nctionality enables time synchronization of sec red LANs with
official time from NTP servers available p blicly on line in Internet (P blic NTP Servers).
NTS-4000 time server can be sed as a s pport for another NTS-4000 server, delivering time into
a sec red LAN isolated from the Internet. This sol tion req ires 2x NTS-4000 servers working
together. In the latter instance, first NTS-4000 works as an antenna em lator (STRATUM-0) for
another NTS-4000, enabling safe time synchronization (no TCP IP comm nication) between.
01/22/2008 Page 16/41

ELPROMA Electronics Network Time Service
9.NTS 4000 software Setup
For the very first time of installation the NTS–4000 has to be config red by resetting to
defa lts val es. Please press and hold sim ltaneo sly “OK” and “C” b ttons on front panel
keyboard. The settings will be displayed on front panel LCD.
Yo will have to config re one of yo r local comp ter (in example laptop) to IP n mber
and MASK which is s itable to connect to the nit or set p basic IP config ration as described in
“Powering NTS-4000” section sing device b ilt-in keyboard. Yo can simply choose the same
prefix as NTS–4000. IP n mber and choose other s ffix digit. The MASK sho ld be set to the
same val e as in NTS–4000.
Please se yo r favorite TELNET or SSH client to connect to the nit sing defa lt val es.
Once terminal is connected the set p appears a tomatically.
Yo can also se yo r favorite web browser to set p NTS via WWW interface.
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ELPROMA Electronics Network Time Service
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Figure 12: Main menu

ELPROMA Electronics Network Time Service
To start config ration yo sho ld first config re all LAN interfaces by simply placing IP,
MASK, DEFAULT GETEWAY for each Ethernet card (LAN1, LAN2).
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Figure 13: Entering IP address
Figure 14: Entering MASK address

ELPROMA Electronics Network Time Service
In addition yo can specify what mode yo want to work NTS–4000 on specific LAN
interface. Yo can enable extra broadcast and m lticast modes r nning in the backgro nd of
standard client/server mode, b t we s ggest to finish basic config ration first before yo go to
more advanced options. Therefore please leave those options for the moment now by simply
filling fields 0.
Now its time to decide what other remote services yo like to keep active for f t re
accessing of NTS–4000. Yo access each LAN separately:
•Enable/Disable access via Telnet
•Enable/Disable access via SSH
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Figure 15: Entering DEFAULT GATEWAY address
Figure 16: Entering IPv6 address