Somerdata R2D3-ASSY-0130, Установка и эксплуатация

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R
2
D
3
Data Capture Card
E1 (G.703/G.704) Frame Recognition
Card versions: R2D3-ASSY-0326 (BNC connectors)
R2D3-ASSY-0327 (RJ-45 connectors)
R2D3-ASSY-0426 (BNC connectors)
R2D3-ASSY-0427 (RJ-45 connectors)
R2D3 cards provide frame synchronisation support for ITU
(G.703/G.704) signals as described below.
When set to UNFRAMED , incoming data will be transferred to
the buffer as soon as START has been commanded.
When set to FRAMED , Incoming data will only be transferred
to the buffer once three consecutive frame alignment words (to
ITU G.704) have been received in the form
S0011011 (where
S is a signalling bit.
The stream will only be deemed to be locked if 3 frames have
been received with 2 valid frame alignment words as above,
alternated with the alternate frame alignment word in the form
S1ASSSS (where S are signalling bits and A is the remote
alarm indicator).
Once locked, the stream will stay locked unless 3 consecutive
frame alignments fail to be found in the expected bit positions.
In the event of this occurring, the locking procedure as
described above will recommence.
If the stream has already commenced recording, the received
data will be faithfully passed through to be recorded.
The only exception to this is if on re-locking, the frame is no
longer in the same relative word position as under the
previous lock condition.
In this event up to 15 bits will be lost while word-alignment is
implemented.
Installation and Operation 5-2