XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
14.4
T1 Super Frame Format (SF)
The Superframe Format (SF), is also referred to as the D4 format. The requirement for associated signaling in
frames 6 and 12 dictates that the frames be distinguishable. This leads to a multiframe structure consisting of
12 frames per superframe (SF) as shown in Figure 111 and Table 178. This structure of frames and
multiframes is defined by the F-bit pattern. The F-bit is designated alternately as an Ft bit (terminal framing bit)
or Fs bit (signalling framing bit). The Ft bit carries a pattern of alternating zeros and ones (101010) in odd
frames that defines the boundaries so that one timeslot may be distinguished from another. The Fs bit carries
a pattern of (001110) in even frames and defines the multiframe boundaries so that one frame may be
distinguished from another.
FIGURE 111. T1 SUPERFRAME PCM FORMAT
SignallingInformation
Bit 7
B
A
During:
Frame12
Frame6
8 Bitsper Timeslot
Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7
Ft
or
Fs
24TimeslotsperFrame
Frame = 193 Bits
TS
1
TS
TS
TS
TS
Ft
or
Fs
------------------
------------------
-------------------
-------------------
TS
1
TS
13
TS
24
2
2
13
24
FR
FR
FR
2
FR
7
FR
11
11
FR
12
12
Multiframe
SF = 12 Frames
------------------
------------------
-------------------
-------------------
FR
2
FR
7
FR
FR
1
1
256
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