Bt8370/8375/8376
AppendixA
Fully Integrated T1/E1 Framer and Line Interface
A.4 Extended Superframe Format (ESF)
A.4 Extended Superframe Format (ESF)
In Extended Superframe Format (ESF) Figure A-2, and Table A-4, the
multiframe structure is extended to 24 frames. The channel 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 reliability of the receiver's framing algorithm.
Figure A-2. T1 Extended Superframe PCM Format
Signalling Information
Bit 8
D
During:
C
B
8 Bits per Channel
3
Frame 24
Frame 18
Frame 12
Frame 6
A
1
2
4
5
6
7
8
CRC
FDL
FPS
or
Fs
CH CH
CH
13
CH
24
24 Channels per Frame
Frame = 193 Bits
1
2
FR
1
FR
2
FR
13
FR
23
FR
24
Multiframe
ESF = 24 Frames
N8370DSE
Conexant
A-5
CONEXANT [ CONEXANT SYSTEMS, INC ]
