xr
PRELIMINARY
XRT86VL38
REV. P1.0.6
OCTAL T1/E1/J1 FRAMER/LIU COMBO
412
13.1.2
Non-FAS Frame
Timeslot 0 within the non-FAS E1 frame contains bits that support signaling or data link message transmission.
The bit-format of timeslot 0 is presented in Table 187. The Si bit in the Non-FAS frame typically carries a
specific value that will be used by the Receive E1 Framer for CRC Multi-frame alignment purposes.
T
ABLE
187: B
IT
F
ORMAT
OF
T
IMESLOT
0
OCTET
WITHIN
A
N
ON
-FAS E1 F
RAME
B
IT
0
1
2
3
4
5
6
7
Value
Si
1
A
Sa4 Sa5 Sa6 Sa7 Sa8
Function6
International Bit
Fixed Value
Yellow Alarm
National bits
Description-
Operation
International Bit
The Si bit within the non-
FAS E1 Frame typically
carries a specific value
that will be used by the
Receive E1 Framer for
CRC Multi-frame align-
ment purposes.
Fixed at “1”
Bit-field “1” contains a
fixed value “1”. This bit-
field will be used for
FAS framing synchroni-
zation/alignment pur-
poses by the Remote
Receive E1 Framer.
FAS Frame Yellow Alarm Bit
This bit-field is used to
transmit a Yellow alarm to
the Remote Terminal. This
bit-field is set to “0” during
normal conditions, and is set
to “1” whenever the Receive
E1 Framer detects an LOS
(Loss of Signal) or LOF
(Loss of Framing) condition
in the incoming E1 frame
data.
National Bits
These bit-fields can be
used to carry data link
information from the Local
transmitting terminal to
the Remote receiving ter-
minal. Since the National
bits only exist in the non-
FAS frames, they offer a
maximum signaling data
link bandwidth of 20kbps.