Frequency Electronics, Inc. FEI-Zyfer, Inc.
GPS Time and Frequency Systems

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System Features:

Full Redundancy:  
    Dual GPS Reference
    Dual Power Inputs

Rugged 2U Chassis:
200+ Option Modules

GPS Receivers:
Standard Civil C/A-Code
    and/or SAASM MPE-S
    Force 22E MRU Military

User Interface:
Standard RS-232
    Optional Ethernet I/O
    (Telnet, SNMP)
    Keypad, LCD display

 Remote Access Utility:
     Zyfer™ Monitor

Standard Outputs:
1 PPS, 10 MHz
     (Front Panel)   

All units are calibrated with
     an in-house standard
     traceable to UTC


Optional Expansion Configuration


CommSync II-D Model 407

The CommSync II-D can provide a wide variety of time and frequency output signals with 8 I/O Module slots and 200+ available Option Modules. Utilized as a Primary Reference Source (PRS), the CommSync II-D provides either Standard Positioning Service (SPS) or the very latest in GPS military technology; SAASM Precision Positioning Service (PPS) (for authorized users only).

The CommSync II-D delivers all the performance and functionality of the CommSync II in a 2U chassis. The heart of the CommSync II-D is the GPS Time and Frequency (GTF) reference module. The GTF is a hot-swappable, front panel plug-in module (with two slots available for redundancy). It is a self-contained module with Quartz Crystal (OCXO) or Rubidium Atomic oscillator options, as well as Civil or SAASM MPE-S GB-GRAM, or SAASM Force 22E MRU GPS receiver options. Dual Power Supplies and Reference Modules provide redundancy with uninterrupted automatic switchover.

Like our flagship CommSync II, the CommSync II-D provides a frequency accuracy of 1E-12 and a time accuracy of < 50 ns Peak to UTC.  Additional I/O slots can be utilized by configuring a slaved CommSync II-D with Distribution Time and Frequency (DTF) modules.

For Monitor and Control functions there is an RS-232 communications port on the front panel of the GTF/DTF module, a front panel keypad and display, as well as optional Gigabit Ethernet plug-in modules providing Telnet, SNMP, PTP v2 (1588-2008), and Network Time Protocol. Zyfer Monitor (FEI-Zyfer's remote access utility) provides complete remote control, including system status, setup, alarm logging and user management over a standard TCP/IP connection.

Rear Panel View
CommSync II-D™ Compact Redundant Modular Time & Frequency System

Dual Antenna

8 Input / Output
Hot-Swappable Option Module Slots


Power Supplies
AC or DC
Hot Swappable


Available Option Modules for CommSync II and GSync Products

CSII Power Supply System Control Modules Frequency Output Modules Time Output Modules Frequency Output Modules GTF Module Antenna Kit
Clock Rate
   Output Specifications (a)  
  Frequency Accuracy:  
 24 Hour Average  Rubidium Oscillator  Quartz Oscillator
 Locked to GPS  < 1E-12  < 1E-12
 Holdover (b) - first 24 hours  < 5E-11  < 1E-10
  Time Accuracy: - to UTC, for calibrated units (c)  
   Rubidium Oscillator  Quartz Oscillator
 Locked to GPS  < 50 ns Peak  < 50 ns Peak
 Holdover (b) - first 24 hours  < 3 μs  < 7 μs
  Short Term Stability (d) typical:  
 Allan Deviation  Rubidium Oscillator  Quartz Oscillator
 1 sec  < 3E-11  < 1E-11
 10 sec  < 1E-11  < 1E-11
 100 sec  < 3E-12  < 1E-10
  Phase Noise (d) typical:  
   Standard Output  Low Noise 5MHz
 1 Hz  < -90 dBc/Hz  < -105 dBc/Hz
 10 Hz  < -105 dBc/Hz  < -130 dBc/Hz
 100 Hz  < -125 dBc/Hz  < -150 dBc/Hz
 1 kHz  < -135 dBc/Hz  < -158 dBc/Hz
   GPS Receiver Options  
 Standard GPS Receiver - Civil C/A-Code:
 Type:  8 to 12 channel, independent tracking
 Frequency:  1575.42 MHz (L1)
 Code:  C/A
 Acquisition Time:  Warm Start: < 2 minutes, Cold Start: < 20 minutes.
 SAASM GPS Receiver - Military P(Y)-Code:
 Type:  12 channel, independent tracking
 Frequency:  1575.42 MHz and 1227.60 MHz (L1 & L2)
 Code:  C/A and P(Y)
 Acquisition Time: (c)  Warm Start: < 2 minutes
 Hot/Cold Start: Dependent on Initialization Device
 Keyload Interface:  DS-102
 FORCE 22E MRU SAASM GPS Receiver - Military C/A and P(Y)-Code: (e)
 Type:  24 channel, simultaneous tracking of L1, L2 and C/A codes
 Frequency:  1575.42 MHz and 1227.60 MHz (L1 & L2)
 Code:  C/A and P(Y)
 Acquisition Time: (c)  Warm Start: < 2 minutes
 Hot/Cold Start: Dependent on Initialization Device
 Keyload Interface:  DS-102
   Input/Output (GTF Front Panel)  
  Reference Option Info  
 Standard GPS Receiver  SAASM GPS Receiver (e)
 1 PPS, 50 Ω, TTL level, SMA, Ext. Sync Input  1 PPS, 50 Ω, TTL level, SMA, External Sync Input
 RS-232 I/O connector  RS-232 I/O connector
 10 MHz, 50 Ω, TTL level, SMA connector  10 MHz, 50 Ω, TTL level, SMA connector
 1 PPS, 50 Ω, TTL level, SMA connector  1 PPS, 50 Ω, TTL level, SMA connector
   Keyload Interface - DS-102
   Hot Start connector (optional)
   Power Options  
  Power Options Info  
Several Power Input options are available, including single or dual modules (for redundancy), 115/230 VAC 50/60 Hz, 12 VDC or 48 VDC, or a combination of AC and DC Power Input modules.
   Chassis Physical Dimensions  
 Height:  87 mm (3.50") (2U)
 Width:  438 mm (17.25") (19" EIA Rack)
 Depth:  419 mm (16.5") including connectors
 Weight:  27 lbs. (max.)
 Operating Temperature:  0° C to 50° C
 Rate of Change:  10° C/Hour
 Storage  Temperature:  -40° C to +85° C
 Relative Humidity:  5 % to 95 %, non-condensing
 Altitude, Operating:  -60 m to 4000 m
 Altitude, Storage:  -60 m to 9000 m
(a) After 24 hours of GPS locked operation, fixed antenna location, antenna delays entered.
(b) After 48 hours of continuous operation.
(c) 2σ (95.5 % probability).
(d) Detailed specifications for various output modules: See "Option Module User's Manual 385-8003".
(e) U.S. Government policy restricts the sale of Precise Positioning Service (PPS) equipment to those
authorized by the U.S. Department of Defense. Non-U.S. authorized users must purchase PPS equipment
through the Foreign Military Sales (FMS) process.
(f) Dependent on the accuracy of initialization parameters from PLGR or DAGR handheld SAASM GB-GRAM receivers, or other initialization devices.

Product specifications subject to change without notice.


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