XRT86VL30
17
SINGLE T1/E1/J1 FRAMER/LIU COMBO - T1 REGISTER DESCRIPTION
REV. 1.0.1
5-4
YEL[1:0]
R/W
00
Yellow Alarm (RAI) Duration and Format
The exact function of these bits depends on whether or not the one-second yellow
alarm rule is enforced. (Bit 7 of this register). The decoding of these bits are
explained in Table 7 and Table 8 below.
TABLE 6: ALARM GENERATION REGISTER (AGR)
HEX ADDRESS: 0X0108
BIT
FUNCTION
TYPE DEFAULT
DESCRIPTION-OPERATION
TABLE 7: YELLOW ALARM DURATION AND FORMAT WHEN ONE SECOND RULE IS NOT
ENFORCED
YEL[1:0]
YELLOW ALARM DURATION AND FORMAT
00
Disable the transmission of yellow alarm
01
SF or N mode:
RAI is transmitted as bit 2 = 0 (second MSB) in all DS0 data chan-
nel.
T1DM mode:
RAI is transmitted as Y-bit = 0 (6th bit in the SYNC byte).
ESF mode:
1. If YEL[0] bit is set ’high’ for a duration shorter or equal to the
time
required
to
transmit
255
patterns
of
1111_1111_0000_0000 on the 4-kbit/s data link bits (M1-
M12),
RAI
is
transmitted
for
255
patterns.of
1111_1111_0000_0000 (approximately 1 second)
2. If YEL[0] bit is set ’high’ for a duration longer than the time
required to transmit 255 patterns of 1111_1111_0000_0000
on the 4-kbit/s data link bits (M1-M12), RAI transmission
continues until YEL[0] bit is set ’low’.
3. If
YEL[0]
bit
forms
another
pulse
during
the
RAI
transmission, it resets the pattern counter and extends the
RAI
duration
for
another
255
patterns
of
1111_1111_0000_0000. (approximately 1 second)
10
SF mode:
RAI is transmitted as a “1” in the Fs bit of frame 12 (This is RAI for
J1 SF standard).
T1DM mode:
RAI is transmitted as Y-bit = 0 (6th bit in the SYNC byte).
ESF mode:
RAI is controlled by the duration of YEL[1] bit. This allows continu-
ous RAI of any length.
11
SF, N, and T1DM mode:
RAI format is the same as described above when YEL[1:0] is set
to’01’.
ESF mode:
RAI duration is the same as described above when YEL[1:0] is set
to’01’, except that format of RAI is transmitted as 255 patterns of
1111_1111_1111_1111 (sixteen ones) on the 4kbits/s data link bits
instead of 255 patterns of 1111_1111_0000_0000.
NOTE: 255 patterns of 1111_1111_1111_111 is the J1 ESF RAI
standard)