SR Series GPS \ MSF \ DCF77 NTP Network Time Servers

TimeTools SR Series NTP Network Time Servers – a range of Linux-based true Stratum 1 Time Servers that provide a real breakthrough in price and performance.


PLEASE NOTE: TimeTools SR Series has now been superseded by the T300 GPS NTP Server Appliance and T550 Multi-GNSS NTP Server .


GPS \ MSF \ DCF-77 NTP Network Time Server


Key Features

  • Linux Based True Stratum 1 NTP Time Servers.
  • Easily Configurable Using Secure Web Interface.
  • Single and Dual Independent LAN Options.
  • GPS, DCF-77, MSF and Dual Reference Capability.
  • Peering and Stratum 2 Operation using external NTP servers.
  • High Stability TCXO Options for Extended Holdover.
  • Universal 100-250VAC 50-60Hz PSU (9-36VDC and 85-250VDC IN options).


  • Accurately Synchronize Microsoft Windows, Linux, UNIX, Routers, Switches, CCTV, DVR’s and other NTP\SNTP Compatible Clients.
  • Simple to Install, Configure and Maintain.
  • Synchronize Thousands of Network Time Clients.
  • Accurately Synchronize Time Critical Processes.
  • Accurate, Traceable Time Reference Inside Your Firewall.

Product Description

TimeTools SR Series NTP servers are a range of Linux-based true Stratum 1 NTP Network Time Servers that provide a real breakthrough in price and performance.

Housed in a rugged, yet compact, 1U high, rack-mountable enclosure, the SR series takes up minimal valuable rack-space.

By utilising a customized Linux kernel and an unmodified version of the latest network time protocol distribution, NTP version 4.2, the SR series offers true NTP/SNTP functionality.

TimeTools SR Series NTP Server - Rear Panel Closeup


“The SR series provides a reliable, highly accurate, traceable, source of time inside your firewall”.

UPDATE !!! The SR/SC series is now provided with a cutting-edge high-sensitivity GPS receiver that can often operate with an indoor located GPS antenna. Additionally, the new receivers can operate from a single satellite-in-view making operation from a window often possible. These features potentially provide a great saving on installation costs when compared to traditional roof-mounted GPS antennas. Of course, our GPS antennas are completely weather-proof and can still be roof-mounted, if required.

Multiple Reference Clock Options

Multiple optional external reference clock combinations can be provided with the SR and SC series; GPS, MSF radio, DCF-77 radio and dual GPS / radio reference capabilities. They provide true flexibility along with high stability and performance.

High-stability disciplined TCXO oscillator options are available to maintain accurate time for extended periods in the event of GPS / radio reference clock signal loss. Additionally, external NTP servers can be utilized to provide peering and stratum 2 operation.

T-3072 GPS Timing Antenna


Easy to Configure and Maintain

An easy to use password-protected web interface is provided for system configuration and management. FTP can be utilised to download NTP statistics and upload firmware upgrades, provided by TimeTools free of charge.

Industry Leading 5-Year Warranty

The SR Series NTP Servers are low-power, convection cooled, devices with no moving parts, aiding long-term reliability. Our confidence in the reliability of the SR range of devices is reflected in the provision of an industry leading 5-year warranty.

SR Series Models

SR7110 – LF / GPS Referenced

The SR7110 is an entry-level Linux-based true NTP time-server at highly competitive price. It can utilise GPS or LF radio time references to provide stratum 1 NTP functionality, ideal for synchronizing digital wall clocks and smaller networks.

SR9210 – LF / GPS / Dual Referenced

The mid-range SR9210 provides a high specification NTP network time reference. It incorporates a high-throughput Ethernet network interface, combined with the ability to accept GPS, LF radio or dual reference GPS / LF external time references. The SR9210 is an ideal time reference where a large number of network time clients are to be synchronised accurately and reliably.

SR9750 – LF / GPS / Dual Referenced with TCXO Oscillator

The SR9750 has all of the advanced features of the SR9210 but also incorporates a high-stability GPS disciplined Temperature Controlled Crystal Oscillator (TCXO). The high precision TCXO backup reference clock provides extended holdover periods in the event of primary reference signal loss.

SR9860D – Dual LAN, High Accuracy, LF / GPS / Dual Referenced with TCXO Oscillator

The top-of-range SR9860D incorporates dual independent LAN capability for synchronizing multiple networks. It also provides enhanced precision along with a GPS/LF disciplined TCXO for extended holdover. Ideal for reliably synchronizing multiple, large, networks with a high degree of accuracy.

Customer Testimonials

Just installed our first SR9210. We were quite surprised about the craftsmanship and quality of the product. The software seems to be engineered very well too. We were able to complete the set-up within a time frame of one hour from first power on to full configuration – and we wrote the documentation for our configuration in parallel. We are using GPS, DCF-77 and three pools for fail-over reasons. Did some fail-over tests too – everything worked as expected. If anyone asks me for advice on a ntp time-server, my answer will be: go to TimeTools and place your order. Thank You very much.
Matthias Petz, ICT Systems Engineer and Project Manager
Strüby Konzept AG, Sweden

See more Customer Feedback and Testimonials.


[wptabs style=”wpui-light” effect=”fade” mode=”horizontal”][wptabtitle]Features[/wptabtitle] [wptabcontent]

Model Comparison Chart

   LAN 10/100 MBit BaseT , RJ-45 auto-sensing
Timing Protocols
   NTP v2, v3, v4, SNTP v3, v4
   NTP Peering
   NTP Broadcast
   NTP MD5 Authentication
   NTP Requests / Second (typical)
> 200
> 1000
> 1000
   Maximum Number of NTP Clients (typical)
> 64,000
> 64,000
   NMEA RS-232 Output
Time Reference Options
   12 Channel GPS Receiver High Sensitivity Indoor,
Over-Determined Clock, Single Satellite Operation
   LF – MSF (UK) Reference Clock
   LF – DCF-77 (German) Reference Clock
   Dual GPS and LF Radio Reference Clocks
Monitoring and Reporting
   SNMP v1 / v2c Trap Alarms (Can be disabled)
   System Logging (SysLog)
   Remote System Logging (Remote Syslog)
   GPS Satellites in View & Signal to Noise Ratio (SNR)
Configuration Protocols
   HTTP (Web) / HTTPS (SSL Secure Sockets Layer)
   SSH (Secure Shell), SCP (Secure Copy Protocol)
   Console (RS-232)
Oscillator Options
   Standard Crystal Oscillator
   High Stability GPS\LF Disciplined TCXO Oscillator
Timing (Typical)
   GPS Accuracy
1 msec
60 nsec
60 nsec
 60 nsec
   LF Accuracy
10-50 msec
1-20 msec
1-20 msec
 1-20 msec
   NTP Accuracy (typical, GPS Synchronised)
<10 msec
< 250 usec
< 250 usec
 <1 usec
   24 Hour Holdover (GPS disciplined, typical @ 25C)
<±10 msec (2.3e10-7)
 <±4.3msec (1e10-7)
   Buffered 1 PPS Output on BNC


[/wptabcontent][wptabtitle]Specification[/wptabtitle] [wptabcontent]

Mechanical\Environmental Specification

Dimensions 483 x 205 x 44 mm (19.0″ x 8.05″ x 1.73″)
Construction 1U High 19″ Rack mount, 1.8mm Aluminium
Weight approx 2.2Kg (4.84lbs)
Power Supply Universal 100-250 VAC 50- Hz CE/UL/CSA Approved PSU
(Optional 9-36V DC IN and 85-250V DC IN versions available)
Power Consumption approx 5W
Operating Temperature 0C ~ +50C (Extended temperature range options available)
Storage Temperature -10C ~ +60C (Extended temperature range options available)
Relative Humidity 95% non-condensing
Approvals CE, EN61000-6-1, EN61000-6-3


Input\Output Specification

LAN 10/100 MBit BaseT , RJ-45 auto-sensing
Serial Console 9 way ‘D’ RS232, 9600, N, 8, 1
GPS Input TNC female
LF/AUX Input: 9 way ‘D’
Power Double Fused IEC Inlet
PPS (optional) Buffered pulse per second output on BNC (optional)

Integral GPS Receiver Specification

Type True GPS Timing Receiver, 12 Channel, L1 1575.42 MHz
Features High sensitivity, Over-determined clock modes, Single satellite in view
Timing GPS Time Traceable to UTC (USNO)
Accuracy +/- 60 nsec UTC (typical)
Acquisition (Cold Start) 38 sec

[/wptabcontent][wptabtitle]Product Codes[/wptabtitle] [wptabcontent]

SR Series NTP Time Servers Product Codes

SR 7110 GPS \ LF NTP Server SR7110-20P
SR 9210 GPS \ LF \ Dual Reference NTP Server SR9210-20P
SR 9750 GPS \ LF \ Dual Reference NTP Server with TCXO SR9750-20P
SR 9860D GPS \ LF \ Dual Reference NTP Server with TCXO SR9860D-20P
Scope of Supply: SR Series NTP Time Server, IEC Mains Lead,
Console Configuration Cable, Product User Guide and NTP Client CD.

(Optional 9-36VDC IN, 85-250VDC IN and extended temperature range versions available.)


Optional SR Series GPS Reference Clock Antennas and Accessories

Jam-Resistant Pole Mounting GPS Antenna and Mount T-3072
30m RG58 Cable TCX-030
50m LMR195 Cable TCX-050
100m LMR400 Cable TCX-100
Additional cable lengths available on request
GPS Surge Suppressor SPP-GPS
GPS Amplifier – 20db T-AD200-8
LF / GPS over optical fibre systems P.O.A
GPS Splitters – 2 to 32 way, compact or rack-mount P.O.A


Optional SR Series LF (Radio) Reference Clock Antennas

Ultra-High-Gain MSF (UK) Antenna SR-MXS-00
Ultra-High-Gain DCF-77 (German) Antenna SR-DXS-00
LF Radio Surge Suppressor LF-SPP



Warranty & Support

  • Industry Leading 5-Year Warranty
  • Free Unlimited Lifetime Support
  • Free Lifetime Firmware Updates

Datasheets and User Guides


PDF Download SR Series Data Sheet and Product Comparison Chart (PDF, 404KB)
PDF Download T-3072 GPS Timing Antenna Data Sheet (PDF, 160KB)
PDF Download SR/SC Series User Guide (PDF, 1.7MB)

How To Buy Our Products

We sell directly to you!

Our products are generally available from stock and can be shipped world-wide.

Contact us for a quotation, advice or to set up an account.

We also accept credit card payments, including Visa and MasterCard.

Request a quotation

Alternatively, please feel free to contact one of our re-sellers in your region.

About TimeTools

TimeTools is a leading UK manufacturer of NTP Network Time Servers, Synchronized Time Displays and Precision Timing Equipment. Since 2002, we have been providing timing equipment to high-profile companies world-wide. Here is a selection of well-known companies who trust TimeTools for their timing requirements:

Small Selection of TimeTools Customers

See more Customer References.

See more Customer Feedback and Testimonials.

ISO9001 Accreditation

Quality and customer satisfaction  is of paramount importance to us. TimeTools is an ISO9001:2008 accredited company. ISO9001 is an internationally recognized standard for quality management.

ISO9001:2008 Registered Company

TimeTools is also a member of the CE Marking Association. An organization which facilitates us with meeting our legal obligations with regards to CE Marking and product conformity for the sale of products within the EU. It also allows us to keep up-to-date with changes in EU legislation.

TimeTools is a member of the CE Marking Association


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