GP-4100 is a high-performance, high-reliability GPS Primary Reference Clock and IEEE-1588v2 PTP Grandmaster that provides ITU-T G.811 Primary Synchronization Frequency References which are locked to a user selected Satellite source. The GP-4100 Satellite Receiver also has an integrated, high bandwidth NTP Server engine that is capable of handling up to 5000 NTP requests per second. Multiple IRIG-B Outputs are also provided to synchronize local clock (time-of-day) display units as well as RTUs to a central timing source with nanosecond accuracy.

PTP Grandmaster with G.811 Frequency outputs

The GP-4100, Primary Reference (PRC) Clock is specifically designed for frequency synchronization of 2G, 3G, HetNet and LTE mobile telecommunications networks as well as backhaul wire-line SDH / SONET and Synchronous Ethernet networks. It may be also used by Railways, Airports (and air-traffic control), Power generation and distribution companies and other Utility companies who not only require highly precise G.811 frequency synchronization locked to a GPS Reference but who also need to provide an accurate time-of-day reference in their networks.

The GP-4100 incorporates up to dual (1+1 redundant) GPS receiver engines and dual (1+1 redundant) power supply options for added reliability which are always locked to a user selected satellite (GPS) reference to provide multiple G.811 / Stratum 1 quality frequency and time-of-day (PTP, NTP and IRIG-B) outputs. The GP-4100 is also equipped highly accurate, low-noise OCXO / Rubidium oscillator which provides a high stability holdover clock that is typical of a Network SSU in the event of the GPS signal, or its antenna failure.


IEEE-1588v2 PTP

PTP Grandmaster with integrated NTP Server

ITU-T G.811 compliant

2.048MHz and 10MHz frequency outputs

Phase Locked Frequency Outputs

1 / 2.048 / 5 / 10MHz output

Standard PTP Profiles

Default, Telecom, Power, SMPTE, Telecom2 and Power2

OCXO Holdover

Accurate timekeeping in holdover

1 + 1 GPS/GNSS Reciever

Fully redundant reciever and antenna

High performance NTP server

Supports up to 3000 NTP requests per second

Supported Protocols



  • Reliable, Cost-Efficient Reference GPS Receiver
  • 50 Channel GPS, L1 frequency, C/A Code Receiver
  • Tracks up to 12 GPS Satellites
  • Concurrent tracking of up to a total of 34 Satellites
  • ITU-T G.811 Primary Reference (PRC) Clock
  • GPS locked G.703 compliant 1.544Mbits, 2.048MBits, 2.048 MHz, 1 PPS and 1 PPM outputs
  • SSM Message format Compliant with ITU-T G.704. Optional GR-378-CORE for SONET Networks
  • ITU-T G.811 / Stratum 1 compliant (PR) Primary Reference when locked to GPS
  • Primary reference and holdover functionality.
  • ITU-T G.812 compliant holdover
  • Leap Second Support
  • MD5 authentication for NTP clients
  • 1/5/10 MHz output
  • IRIG-B outputs
  • Standard RJ45 and BNC connectors for all inputs and outputs
  • ToD compliant to NMEA 0183 (DB9 Serial Port)
  • LCD display with back light.

Additional Features:

  • IEEE - 1588v2 PTP Grandmaster
  • High bandwidth NTP Server capable of supporting up to 5000 NTP requests per second
  • IPv4 and IPv6 compatible NTP Server
  • SSH, Telnet, Radius, SNMP V2 MIB, Password Protection
  • Redundant AC and DC power supply options
  • 4, 10/100/1000BaseT Network Interface Ethernet Ports
  • Power Contact and Lightening Protection as per Telcordia GR-1089-CORE.

Technical Specifications

Ethernet Interfaces:
Number of Ethernet Ports 6
Type RJ-45
Interfaces (4) 10/100BaseT Ethernet Interfaces: NTP Server
(1) 10/100/1000 Gigabit Ethernet Interface: Management + NTP Server
(1) 10/100/1000 Gigabit Ethernet Interface: IEEE-1588v2
Synchronization Outputs
IRIG-B (6) Unmodulated (50 Ohm BNC)- B000, B002, B003, B004, B005, B006, B007
Frequency (50 Ohm BNC) (8) 2.048MHz
(1) 1/5/10MHz
(1) 1 PPS
(1) Programmable - 1PPS to 1PPD
Time of Day (1) NMEA 0183 (RS232)
2.048Mbits - E1
1.544Mbits - T1
(8) RJ-45
Synchronization Inputs
External Input (1) 2.048MHz (75 Ohms BNC)
(1) 10MHz (50 Ohms BNC)
(1) 2.048 Mbits (BNC)
Power Supply Options
AC Input 100V~240V AC
1+1 Redundant 100V~240V AC
DC Input 48V DC (1+1 Optional)
110V DC (1+1 Optional)
AC + DC Input 48V DC + 100V~240V AC
GPS/GNSS Receiver Specifications:
  • 50 Channel GPS Receiver
  • 72 Channel GNSS Receiver
  • GPS L1 frequency, C/A Code Receiver
  • Tracks up to 12 satellites simultaneously
  • Synchronizing Time:
    • Acquisition time - Hot Start: Less than 15 sec.
    • Acquisition time - Warm Start: Less than 45 sec.
    • Acquisition time - Cold Start: Less than 140 sec.
  • GPS Signal
    • Tracking and Navigation: -162 dBm
    • Reacquisition -160 dBm
    • Cold Start -148 dBm
  • Integrated GPS Antenna
  • Accuracy of Time-Pulse Signal referenced to GPS: +/-30ns (raw), in Stationary Mode
  • Accuracy of Time-Pulse Signal referenced to GNSS: +/-20ns (raw) in Stationary Mode
  • Accuracy of Time-Pulse Signal referenced to GPS/GNSS: +/-15ns (compensated)
    (Note: with all satellites in view at -130db)
  • User configurable for “Stationary” or “Moving” Applications. May be configured for use in Portable, Automobile, Maritime Application Modes.
Network Time Protocol:
  • NTP v2, (RFC 1119), NTP v3 (RFC 1305), NTP v4, (RFC 5905), SNTP v3 (RFC 1769), SNTP v4 (RFP 2030), MD5 Authentication
  • Internet Protocol: Ipv4
  • Time Protocol: TIME (RFC 868)
  • Daytime Protocol: DAYTIME (RFC 867)
Frequency Outputs:
  • 1 x 2.048 MHz, 75 Ohms, phase-locked
  • 1 x 10 MHz, 50 Ohms, phase-locked
  • 1 x 1 PPS, phase-locked to UTC (BNC)
PTP IEEE 1588-2008 V2 Grandmaster:
  • <100ns Accuracy when locked with GNSS (GPS/GLONASS) in Stationary Mode
  • PTP Slave/Client capacity: 8, 16, 32
  • User Configurable: 1-step and 2-step Clock
PTP Profiles:
  • Default IEEE-1588v2, 2008 PTP Profile
  • Default Power Profile.
  • Power Profile: IEEE C37.238-2011
  • Ethernet Default Profile (Layer 2 multicast)
  • Telecom-2008 Profile (Layer 3 unicast, pre-standard ITU-T G.8265.1, Ipv4)
  • ITU-T G.8265.1 (Layer 3 unicast, Ipv4)
  • Communication: Unicast, Multicast or Mixed
  • Best Master Clock Algorithm (BMCA)
Antenna Specifications:
  • Integrated Antenna
  • Antenna Type: Active
  • Amplifier Gain: Typical 27dB (GPS L1 band)
  • Operating temperature: -40C to +75C
  • Reverse Polarity Protection
  • Lightning Protection: According to EN61000-4-5 Level 4.
Ordering Information


Part Code Description Options
Y+Y Power Supply Option (1+1) / (1+0)
ZZ PSU Input type AC / DC / ACDC
LP Lightning Protection Kit 1 (required) or 0 (not required)


  • Synchronizing Cellular networks like UMTS, GPRS, 3G and LTE
  • Power generation and distribution companies and other utility companies
  • Wireless and Wireline Telecom synchronization
  • Distributing Time (ToD) and Frequency reference for power utilities across all nodes of the network
  • Synchronization of Defense Networks
  • Synchronizing airports and aviation communications
  • Synchronizing railway signalling networks and railway communications
  • Synchronizing traffic management
  • Broadcasting Network and Broadcast equipment synchronization.


Data Sheet (PDF)