3.0 Registers
CX28394/28395/28398
3.9 Receiver Registers
Quad/x16/Octal—T1/E1/J1 Framers
049—Alarm 3 Status (ALM3)
Reports real-time status of the receive framer (not affected by ONESEC latch mode), and miscellaneous latched
error status (SEF and RMAIS). Any change of the logical OR of (FRED or MRED or SRED) status activates
RLOF interrupt [ISR7; addr 004]. Refer to Table 2-2, Criteria for Loss/Recovery of Receive Framer Alignment,
[RFRAME; addr 001] to find the criteria for loss/recovery of frame alignment.
7
6
5
4
3
2
1
0
—
RMAIS
SEF
SRED
MRED
FRED
LOF[1]
LOF[0]
RMAIS
Receive TS16 Alarm Indication Signal (CAS mode only)—RMAIS is latched active high and
cleared by a processor read. Criteria for detection and clearance of RMAIS is per ITU G.775.
Mode
CAS
RMAIS Criteria
Set if TS16 contains three or fewer zeros out of 128 bits in
each mutiframe over two consecutive multiframes (4 ms).
Other
Not applicable (read zero).
SEF
Severely Errored Frame—SEF is latched active high and cleared by a processor read. Criteria
for detection and clearance of SEF is per ANSI T1.231.
Mode
SEF Criteria
E1
Set if two or more (FAS or NFAS) errors detected out of six frames.
(FAS + NFAS, or 2 FAS, or 2 NFAS errors, etc.).
FT/SF/SLC Set if two or more Ft errors are detected out of 3 Ft bits.
ESF Set if two or more FPS errors detected out of six FPS bits.
SRED
MRED
FRED
Loss of CAS Alignment—Real-time status of CAS alignment machine. SRED is applicable if
CAS is enabled, otherwise SRED is zero.
0 = recovery of CAS alignment
1 = loss of CAS alignment
Loss of MFAS Alignment—Real-time status of MFAS alignment machine. MRED is
applicable if MFAS is enabled, otherwise MRED is zero.
0 = recovery of MFAS alignment
1 = loss of MFAS alignment
Loss of T1/FAS Alignment—Real-time status of basic frame alignment machine. FRED alarm
counter [AERR; addr 05A] increments for each low-to-high FRED transition.
0 = recovery of frame alignment
1 = loss of frame alignment
LOF[1:0]
Reason for Loss of Frame Alignment—LOF status is latched whenever FRED reports a loss of
frame alignment and remains held at the latched value until the next loss of frame alignment.
LOF[1:0]
LOF Criteria
00
01
10
11
Three consecutive FAS pattern errors
Three consecutive NFAS pattern errors
915 or more CRC4 errors out of 1000 blocks checked
Eight ms timeout while searching for MFAS
3-48
Conexant
100054E
CONEXANT [ CONEXANT SYSTEMS, INC ]
