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<h1>Call Release after Loss Of TRAU Frame Synchronisation</h1>

<p>If the TRAU looses its frame synchronisation between BTS
and Transcoder for over one second, the BTS sends a connection failure message
with cause remote transcoder failure to the BSC. The BSC releases the call.
The reason for the loss of synchronisation can be for example a failure in
transmission. A switch over to a possible redundant transmission path (for
example loop protection) can take longer than one second.</p>


<p>To maintain the call longer, a new parameter shall be implemented
into the BSC to indicate after how many remote transcoder failures the call
is released. BTS repeats the remote transcoder failure in one second’s periods
until BSC releases the call or the frame synchronisation is obtained again.</p>
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