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Data Sheet
187
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description T1/J1
5.4.4.1
Synchronization Procedure (T1/J1)
For multiframe synchronization, the terminal framing bits (FT-bits) are observed. The synchronous state is
reached if at least one terminal framing candidate is definitely found, or the synchronizer is forced to lock onto the
next available candidate (FMR0.FRS).
5.4.5
12-Frame Multiframe (D4 or SF Format, T1/J1)
Normally, this kind of multiframe structure only makes sense when using the CAS robbed-bit signaling. The
multiframe alignment signal is located at the FS-bit position of every other frame (refer to Table 55).
There are two possibilities of remote alarm (yellow alarm) indication:
Bit 2 = 0 in each time slot of a frame, selected with bit FMR0.SRAF = 0
The last bit of the multiframe alignment signal (bit 1 of frame 12) changes from 0 to 1, selected with bit
FMR0.SRAF = 1.
5.4.5.1
Synchronization Procedure (T1/J1)
In the synchronous state terminal framing (FT-bits) and multiframing (FS-bits) are observed, independently.
Further reaction on framing errors depends on the selected synchronization/resynchronization procedure by
FMR2.SSP = 0: terminal frame and multiframe synchronization are combined. Two errors within 4/5/6 framing
bits (by bits FMR4.SSC(1:0)) of one of the above leads to the asynchronous state for terminal framing and
multiframing. Additionally to the bit FRS0.LFA, loss of multiframe alignment is reported by bit FRS0.LMFA. The
resynchronization procedure starts with synchronizing upon the terminal framing. If the pulse framing has been
regained, the search for multiframe alignment is initiated. Multiframe synchronization has been regained after
two consecutive correct multiframe patterns have been received.
FMR2.SSP = 1: terminal frame and multiframe synchronization are separated Two errors within 4/5/6 terminal
framing bits lead to the same reaction as described above for the “combined” mode. Two errors within 4/5/6
multiframing bits lead to the asynchronous state only for the multiframing. Loss of multiframe alignment is
Table 54
4-Frame Multiframe Structure (T1/J1)
Frame Number
FT
FS
1
2
3
4
1
–
0
–
Service bit
Table 55
12-Frame Multiframe Structure (T1/J1)
Frame Number
FT
FS
Signaling Channel
Designation
1
2
3
4
5
6
7
8
9
10
11
12
1
–
0
–
1
–
0
–
1
–
0
–
0
–
0
–
1
–
1
–
1
–
0
A
B