xr
PRELIMINARY
XRT86VL38
REV. P1.0.6
OCTAL T1/E1/J1 FRAMER/LIU COMBO
418
13.5
T1 Extended Superframe Format (ESF)
In Extended Superframe Format (ESF), as shown in Figure 115 and Table 190, the multiframe structure is
extended to 24 frames. The timeslot structure is identical to D4 (SF) format. Robbed-bit signaling is
accommodated in frame 6 (A-bit), frame 12 (B-bit), frame 18 (C-bit) and frame 24 (D-bit).
The F-bit pattern of ESF contains three functions:
1.
Framing Pattern Sequence (FPS), which defines the frame and multiframe boundaries.
2.
Facility Data Link (FDL), which allows data such as error-performance to be passed within the T1 link.
3.
Cyclic Redundancy Check (CRC), which allows error performance to be monitored and enhances the reli-
ability of the receiver’s framing algorithm.
9
1544
1
----
1-8
----
----
10
1737
----
1
1-8
----
----
11
1930
0
----
1-8
----
----
12
2123
----
0
1-7
8
B
F
IGURE
115. T1 E
XTENDED
S
UPERFRAME
F
ORMAT
T
ABLE
189: S
UPERFRAME
F
ORMAT
F
RAME
B
IT
F-B
ITS
B
IT
U
SE
IN
E
ACH
T
IMESLOT
S
IGNALLING
C
HANNEL
T
ERMINAL
F
RAMING
F
T
T
ERMINAL
F
RAMING
F
S
T
RAFFIC
S
IG
D
C
CRC
CRC
FD
L
FD
L
B
A
Bit
0
Bit
1
Bit
2
Bit
3
Bit
4
Bit
5
Bit
6
Bit
7
8 Bits per
Timeslot
FP
S
o
rF
s
FPS
or
Fs
TS
1
TS
1
TS
2
TS
2
-----------------
-
-----------------
-
TS
13
TS
13
------------------
-
------------------
-
TS
24
TS
24
FR
1
FR
1
FR
2
FR
2
-----------------
-
-----------------
-
FR
13
FR
13
------------------
-
------------------
-
FR
23
FR
23
FR
24
FR
24
Signalling
Information
Bit 7
During:
Frame 24
Frame 18
Frame 12
Frame 6
24 Timeslots per Frame
Frame = 193 Bits
Multiframe
ESF = 24
Frames