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KB01104 - How to use AT-ETU-SYNC to correct clock-stretching issues between a Cisco/Scientific Atlanta cable box and HDBaseT Extenders.


As you may be aware, many Cisco and Scientific Atlanta cable box’s lacks a specific feature in their HDMI signal called clock-stretching. This function causes the signal from the cable box’s to be incompatible when used with HDBaseT extenders which require the use of clock stretching information to pass signal. For more information, please see this article.

One of the best ways to correct this issue is to install the AT-ETU-SYNC between the cable box and the input of HDBaseT extenders. The AT-ETU-SYNC has the ability to re-clock the HDMI signal from the Cisco/Scientific Atlanta cable box and pass this signal through to the HDBaseT extenders which will then pass the signal on to the end destination.

Installing the AT-ETU-SYNC is as easy as placing the unit directly on the HDMI output of the Cisco/Scientific Atlanta cable box to the HDMI IN of the ETU-SYNC and then connecting the HDMI OUT of the ETU-SYNC to the HDMI IN of the HDBaseT extenders transmitter. You can use any USB port on the cable box to power the AT-ETU-SYNC or a standard 5v USB Charger if one is not available. You do not need to worry about learning EDID on the unit, however, if you find any video stability issues after installing the SYNC, feel free to learn EDID following these steps.


Diagram of recommended installation:

Article ID: KB01104 


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