Telecom Solutions DCD 523 Digital Clock
Distributor Network Synchronization System
(w/ Dual Rubidium Oscillators)
Telecom Solutions DCD-LPR Digital Clock Distributor
Local Primary Reference GPS Receiver
Telecom Solutions DCD-LPR-G
Optic Fiber GPS Receiver Antenna

Words from the Seller: This is perhaps the finest network timing system available on the market today. The outstanding performance comes from applying state of the art technology and innovation design to every aspect of the system. First, the DCD-523 has dual rubidium oscillators for state of the art short term timing stability and superior holdover. Secondly, add the unprecedented long term performance of GPS tracking with the GT1 GPS Module...but GPS is only as good as its signal. Third, it is the innovative antenna design which places the receiver front end in the antenna eliminating transmission line losses. The antenna then sends the timing signal over optic fiber to the main receiver. since Optic fiber lines have minimal loss, the approach allow virtually unlimited antenna placement with no performance penalty. Combined with the systems superior build quality and other innovations and you have truly the best system on the market!


DCD 523 Digital Clock

Cards Included:

* (2) STE2 Enhanced Stratum 2 Clock Cards <<(Yes, 2 rubidium clock modules!)
* (2) Clock Input Cards
* (2) TO-CA Timing Output Composite Clock Cards
* (1) TO-TA DS1Output Card
* (1) SA1 Card
* (1) MCA-5 Matrix Controller Card


The DCD-523 is a SYNC AND TIMING distribution system that provides the accurate clock references needed throughout your network to assure reliable synchronization.The DCD-523 platform addresses timing applications from Stratum 1 to Stratum 3. Its system architecture offers the enhanced reliability of a fault-tolerant network to address all existing and future timing/synchronization needs.

Modular design provides optimum flexibility. For example, Primary Reference Clock (PRC) ST1 applications are provided by adding any of the TimeSourceฎ products, or the DCD-LPR (Local Primary Reference) system to the input of the DCD-523 Multi-Reference Controller (MRC).

Or, for slave clock applications, the DCD-523 can be equipped with a variety of clocks, including the ST2E,TNC, and ST3E, with outputs in any timing signal format.

The DCD-523 is backwards compatible with most existing DCD cards.The user can migrate to the DCD-523 and preserve existing quality.

Management of the system is possible via the Version 5 cards. Inputs and outputs to and from the system can be provisioned, alarms and status can be retrieved, and performance data collected can be downloaded to analyze network performance. SSM messaging is supported by the Version 5 cards.

PDF Specs For The DCD 523


  • Provides accurate clock references needed throughout a network
  • System architecture offers the enhanced reliability of a fault-tolerant network to address all existing and future timing/synchronization needs
  • Modular design provides optimum flexibility
  • Backwards compatible with most existing DCD cards



STE2 Enhanced Rubidium Clock Card

The Stratum 2E (ST2E) enhanced rubidium clock represents a revolutionary approach to telecommunications clock design. The ST2E has re-defined the function of a clock to be more than just an oscillator and phase locked loop. Instead, the ST2E has elevated that definition to encompass a control system which can manage multiple oscillators and perform enhanced filtering and reference tracking.

The rubidium atomic oscillator has established itself whenever long term accuracy and stability are required. The ST2E clock design enhances the rubidium technology further by adding a control system that raises the inherent performance level of rubidium and improves its reliability.

The ST2E control system takes feeds from two rubidium oscillators; one from the rubidium oscillator on board the clock card and a second from the oscillator on the mate card. The ST2E also incorporates an on board quartz oscillator for added reliability. Ensembling of the two rubidium oscillators and majority voting with quartz creates a "super rubidium" signal used as the reference for the Symmetricom approach to Direct Digital Synthesis (DSS) clock generation.

In addition, the ST2E uses advanced temperature compensation design techniques that result in a ten to one reduction in temperature sensitivity over other rubidium oscillators.


Cards Included:

* (1) GT1 GPS Timing Interface T1 Card: <<(This provides enhanced GPS tracking of the rebidium oscillators)


The Symmetricom DCD-LPR/C is a front-end primary reference source used with the DCD timing platform for synchronizing digital telecommunications networks, and is fully compliant with CE mark requirements.

The DCD-LPR/C can provide the Primary Reference Source (PRS) required at any key network node, independent of land-line timing distribution. Using readily available radio disseminated services, such as GPS (Global Positioning System), the DCD-LPR/C generates E1 clocking signals which exceed ITU, ANSI and Bellcore requirements for PRS accuracy and stability.

This creates a more survivable network architecture, in which network maintenance and administration are reduced, while performance, reliability, and services are enhanced.

The DCD-LPR/C employs an integrated, roof-mounted GPS antenna and Timing Receiver (GTR). The GTR uses an all-in-view method to ensemble up to six GPS satellite signals with a dynamic averaging technique that mitigrates the effects of Selective Availability (SA). The UTC timing from the GTR is then passed to the GPS Timing Interface (GTI) card in the DCD-LPR/C shelf.

The LCD messages on the front panel of the GTI indicate the current performance of the card or any required diagnostic information.

The DCD-LPR/C system also ensembles the highly stable resonator component from the dual DCD rubidium clocks. A disciplined time-scale is then generated, using the ensemble of the DCD-series clocks steered by the UTC accuracy of GPS timing, and clocks the ouput as a E1 signal format.

The E1 signal becomes the PRS signal to the SSU (Synchronisation Supply Unit) or BITS (Building Integrated Timing Supply) for office clock distribution.

Existing DCD sites can be cost-effectively upgraded to PRC performance with the DCD-LPR/C. This upgrade is built on the use of existing DCD plug-in sets.

Used with the Multi-Reference Controller (MRC) card in a DCD-500 system, the GTI outputs are used in a sophisticated majority scheme that qualifies each input against the other for further enhanced PRC capability and primary reference management functionality.


  • Latest digital technology
  • Easy to install
  • Compliant to ANSI, Telcordia, ETSI, ITU-T, NEBS, and CE/AS standards
  • CE marked


DCD-LPR-G Receiver Antenna

GTR Antenna/Receiver:  <<(This system uses optic fiber connection to the GPS Clock to provide nearly zero signal loss between the Antenna and the GPS Receiver; This allows virtually unlimited options in the antenna placement)

The GTR is a eight-channel parallel receiver that:
• simultaneously tracks up to eight GPS satellites
determines the six best satellite signals in view
derives an ensembled average timing correction input for those six satellites
provides a multiplexed 4-khz synchronization signal incorporated into 1 pulse-per-second timing, and a data communications channel to the GTI. The fibre optic carrier is continuous between the GTR and GTI.

Status messages sent from the GTR to the GTI:

  • GPS
    – Positioning and mode of operation
    – Two-dimensional: longitude and latitude
    – Three-dimensional: longitude, latitude, and height
    – Timing– Latitude, latitude Pole North/South
    – Longitude, longitude Pole East/West
    – UTC time

  • SAL
    – GTR alarm information, e.g., loss of visible satellites, insufficient satellites

  • SFM
    – current status: position or timing recovery

  • SIV
    – satellites in view
    – Track number of satellites
    – Satellite elevation
    – Satellite azimuth
    – Satellite signal-to-noise ratio

  • SSS
     – satellite status
    – Satellite status almanac obtained
    – Position status obtained
    – Part of timing solution

GTR to GTI communication is provided via a two-strand fibre optic cable. The maximum allowable cable length is 1300 Metres.

The GTR is attached to a pipe flange by four nuts. The pipe flange is mounted on a Class C 4 Inch PVC pipe secured to the roof or to a parapet by clamps.






As our many customers will attest, we will do our very best to resolve any customer problems.  But our official policy is: 

  • All items sold carry a 3-day Right Of Return Warranty. 
  • All claims must be made within 3 days of receipt. 
  • All warranties are void if the calibration / warranty seals are broken.


The equipment shown is a representation only.  We often have multiple units in stock so please email us with your needs.  We have a large inventory and can usually find any test and measurement item in a short time frame.------Inquires