
QuadFALC
TM
PEF 22554 E
Functional Description E1
Data Sheet
146
Rev. 1.2, 2006-01-26
S
a6-Bit Detection According to ETS 300233
Four consecutive received S
a6-bits are checked for the combinations defined by ETS
300233. The QuadFALC
TM
detects the following fixed Sa6-bit combinations: SA61, SA62, SA63, SA64 = 1000
B, 1010B, 1100B, 1110B, 1111B.
All other possible 4-bit combinations are grouped to status “X”.
A valid S
a6-bit combination must occur three times in a row. The corresponding status bit in register RSA6S is set.
Register RSA6S is of type “clear on read”. Any status change of the S
a6-bit combinations causes an interrupt
(ISR0.SA6SC).
During the basic frame asynchronous state update of register RSA6S and interrupt status ISR0.SA6SC is
disabled. In multiframe format the detection of the S
a6-bit combinations can be done either synchronously or
asynchronously to the submultiframe (FMR3.SA6SY). In synchronous detection mode updating of register RSA6S
is done in the multiframe synchronous state (FRS0.LMFA = 0). In asynchronous detection mode updating is
independent of the multiframe synchronous state.
S
a6-Bit Error Indication Counters
The S
a6-bit error indication counter CRC2L/H (16 bits) counts the received Sa6-bit sequence 0001B or 0011B in
every CRC submultiframe. In the primary rate access digital section this counter option gives information about
CRC errors reported from the TE by the S
a6 bit. Incrementing is only possible in the multiframe synchronous state.
The S
a6-bit error indication counter CRC3L/H (16 bits) counts the received Sa6-bit sequence 0010B or 0011B in
every CRC submultiframe. In the primary rate access digital section this counter option gives information about
CRC errors detected at T-reference point and reporting them by the S
a6-bit. Incrementing is only possible in the
multiframe synchronous state.
4.4.3.8
E-Bit Access (E1)
Due to signaling requirements, the E-bits of frame 13 and frame 15 of the CRC multiframe can be used to indicate
received errored submultiframes: