CX28394/28395/28398
3.0 Registers
Quad/x16/Octal—T1/E1/J1 Framers
3.12 Transmitter Registers
Table 3-16. T1 Transmit Framer Modes (T1/E1N = 1)
F-bit Overhead Insertion
Yellow Alarms
TFRAME
Framer Mode
Fs
FPS
CRC6
Ft
YEL
MYEL
0000
0100
0101
100X
0001
1100
1101
FT Only
Ones
Yes
Yes
Yes
–
–
–
–
–
Yes
Yes
Yes
Yes
–
YB2
YB2
YJ
–
–
SF
SF + JYEL
SLC
–
–
–
–
–
YB2
YB2
YB2
YB2
–
ESF + No CRC
ESF + Mimic CRC
ESF + Force CRC
Yes
Yes
Yes
Ones
Yes
Yes
YF
YF
YF
–
–
–
–
Table 3-17. Criteria for E1 Loss/Recovery of Transmit Frame Alignment
Mode Description
Basic Frame Alignment (BFA) is recovered when the following search criteria are satisfied:
FAS
•
•
•
FAS pattern (0011011) is found in frame N.
Frame N+1 contains bit 2 equal to 1.
Frame N+2 also contains FAS pattern (0011011).
During FAS only modes, BFA is recovered when the following search criteria are satisfied:
•
•
•
FAS pattern (0011011) is found in frame N.
No mimics of the FAS pattern present in frame N+1.
FAS pattern (0011011) is found in frame N+2.
NOTE(S): If FAS pattern is not found in frame N+2 or FAS mimic is found in frame N+1, then the search
restarts in frame N+2.
Transmit Loss of Frame (TLOF) alignment is declared when:
•
Three consecutive FAS pattern errors are detected, where FAS pattern consists of a 7-bit (x0011011)
pattern in FAS frames as well as bit 2 equalling one in NFAS frames.
MFAS
CAS
MFAS—CRC Multiframe Alignment is recovered when the following search criteria are satisfied:
•
•
•
BFA is recovered, identifying FAS and NFAS frames.
Within 6 ms after BFA, bit 1 of NFAS frames contains the first MFAS pattern (001011xx).
Within 8ms after BFA, bit 1 of NFAS frames contains the second MFAS pattern (001011xx), aligned
to first MFAS.
MFAS errors do not cause Transmit Loss of Frame (TLOF) alignment.
CAS Multiframe Alignment is recovered when the following search criteria are satisfied:
•
•
BFA is recovered, identifying TS0 through TS31.
MAS (0000xxxx) Multiframe Alignment Signal pattern is found in the first 4 bits of TS16, and 8 bits
of TS16 in preceding frame contains nonzero value.
CAS errors do not cause Transmit Loss of Frame (TLOF) alignment.
100054E
Conexant
3-57
CONEXANT [ CONEXANT SYSTEMS, INC ]
