Category Archives: Guides

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New Trusted Source Mode feature by Meinberg

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Andreja Jarc from Meinberg has provided the following information regarding a new Trusted Source Mode feature. In the latest release of our LANTIME firmware 6.24 you can find the new feature. This additional functionality is much awaited by everyone who is looking for a method that will help to mitigate vulnerabilities of the GPS signal.

Anomalies in the GPS timing caused by unfriendly signal spoofing or transmission of incorrect data by the GPS system itself as observed on January 26th 2016 lead either to the loss of reception or even to incorrect time in a GPS synchronized timing receiver, if no additional measures are taken to mitigate the influence of these effects. Meinberg has implemented a so-called ‘trusted source’ method (TRS) – that allows connecting one or more additional time sources to a GPS receiver. The functionality of this kind of receiver with a Multi Reference Source (MRS) operation has been addressed in one of our previous posts.

The TRS Method is supported in Meinberg LANTIME Systems in combination with an external XHE Rubidium connected to the GPS receiver. The TRS enables deeper consistency checks of the received time.

Figure 1: Trusted source setup including LANTIME M3000 with GPS180 receiver and an XHE Rubidium device. In normal operation, the external Rubidium is steered by PPS coming from the GPS clock. In holdover periods, on the other hand, the Rubidium becomes a master source and steers the reference clock with its PPS.

The external Rubidium acts as a holdover buffer that is synchronized by the MRS Master as long as the master is available. If the GPS Master fails or GPS for some reason starts delivering corrupted data the TRS will detect this as an offset limit violation. Consequently, the reference selection algorithm will discard the current master and the XHE rubidium source will become the new master for synchronization.

When the GPS signal reverts to normal operation and the time difference returns below the TRS limit, the GPS becomes the master source again.

Configuration of TRS in LANTIME Systems

Let me now explain the steps how to configure the TRS mode in your LANTIME.

First of all, the GPS source should be selected as source 1 in the priority list and the “ext. OSC” (referring to XHE Rubidium) should be configured as priority 2. All the rest of priority levels should be left unconfigured. You will find these settings in the LANTIME Web GUI-> Clock->GNS Clock->Source Priority.

Figure 2: Priority list with GPS and ext. Osc. in MRS Settings.

Second, the IRSA Reference selection algorithm should be activated.

We configure a TRS limit the GPS Master source should comply with in the Precision field. In our example we configured 250ns which is the maximum allowed time deviation of the GPS receiver.

Figure 3: TRS offset limit for the GPS receiver.

Third, the TRS mode should be enabled by selecting “Use Trusted Source” for the GPS master. (LANTIME Web GUI-> Clock->GNS Clock->Features). The XHE Rubidium should be configured as “Is Trusted Source”.

Figure 4: Activation of the TRS operation mode.

Finally, the GPS source should have enabled “Time of Day Source” and “Phase Source”, which means that the GPS is a source for both Time of Day and Phase. At the XHE Rubidium only the Phase Source should be enabled, since the atomic clock alone does not deliver a time of day information.

Figure 5: Time of Day and Phase information selection.

You can monitor the TRS operation in the MRS Status. As long as the time offset between GPS and XHE does not exceed the GPS precision value the normal operation status is shown as below.

Figure 6: Status information in normal operation.

When the TRS limit is violated, the reference algorithm discards the current master and switches automatically to “ext. OSC” (i.e. XHE Rubidium) backup mode and the “TRS Limit violated” flag is shown in the status information of the GPS source.

The TRS Violation is listed also in the notification event matrics and can be activated for monitoring.

Figure 7: Selection of notification events for alarming and monitoring of the TRS operation.

Let me acknowledge at this point my colleague Andre Hartmann, the Managing Director of R&D at Meinberg for providing the technical expertise on the TRS feature.

I hope you find this post useful for your synchronization deployment. If you have any questions, write me to or visit our website at:

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Room Scheduling made easy with Crestron

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Room scheduling is a common way to make more effective use of meeting spaces. Users get more visibility of rooms that are available, making walk-up meetings a breeze. Likewise, organisations benefit from better visibility of room availability and usage.

Traditionally, room scheduling screens have come as part of an overall audio visual control system. This works well if you have such a control system in place, but it can be hard to justify outside of a new fitout.

Room scheduling without a control system

Crestron’s TSW series of touch-screens are the go-to screen for flexible control in corporate and educational settings. It goes without saying these screens can be programmed to do almost anything, and integrate into a Crestron control system.

However, the Crestron TSW-760 and TSW-1060 can also be configured to run an out-of-the-box room scheduling application. This means no control system, and no need for programming and on-site commissioning services.

The room scheduling app can connect directly to your mail server, and has simple configuration via a web GUI. Users can make walk-up meetings and the door, and browse availability for the rest of the day.

Crestron TSW760 boardroom entry

Compatible with leading mail systems

Crestron’s room scheduling application is compatible with both Microsoft (Office 365 and Exchange on-premise) and Google mail systems. In addition, you can connect to Crestron Fusion for enterprise control of your room scheduling and control systems.

Connecting to a mail server is a simple as providing the room resource mailbox username and password, and the web services URL of your mail server. Each room can be configured in a matter of minutes.

Once connected, the room scheduling panel will poll the mail server for updates and allow direct entry of meetings for ad-hoc usage.

Creston calendar integration


Aesthetic mounting options

Touch screens are available in both white and black, and 7″ or 10″ sizes. In our own boardroom, we decided on the 7″ black screen to match with the existing fittings.

A range of cable ducting and screen mounting solutions are available. Pictured below, we integrated the cable run into the door frame and used the glass adhesive mount for a very “invisible” mounting solution.

As the screens are PoE-powered, only a single cable is required for power and data.

As an option, you can also connect a room status sign directly into the screen, for automated red/green status tally. This lets people see room availability with a quick glance down the corridor.

Crestron meetingroom signs

Greater insight into room usage

Combined with Crestron Fusion, an organisation can get more detailed insights in to room usage through regular reports. On top of that, occupancy sensors and clever programming allow “shadow” meetings (the recurring ones that never actually happen) to be deleted automatically after a period of non-attendance. With CBD real estate costs always on the increase, smart organisation can make sure the cries of “we can never get a free room” are really accurate, and plan accordingly.

Want to know more?

iTkey is a system integrator connecting Everything Over IP. We bridge the gap between audio visual and IT for truly connected systems.

More information on our range of solutions is on the iTkey Audio Visual website.

For more on Enterprise Room Scheduling see this page on the Crestron website.

Or contact us at our Sydney office – to talk to an AV/IT expert.

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