Table 1-A. ESF Format
Overhead Bits
(1 bit per frame)
Bit Use, All 24 Channels
(192 bits per frame)
Signaling Bit Use Options
(see Notes below)
Frame
Number
Fe
FDL
CRC
Traffic
Signaling
T
2
4
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
—
—
—
0
—
—
—
0
—
—
—
1
—
—
—
0
—
—
—
1
—
—
—
1
m
—
m
—
m
—
m
—
m
—
m
—
m
—
m
—
m
—
m
—
m
—
m
—
—
C1
—
—
—
C2
—
—
—
C3
—
—
—
C4
—
—
—
C5
—
—
—
C6
—
—
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-7
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-7
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-7
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-8
Bits 1-7
Bit 8
Bit 8
Bit 8
Bit 8
—
—
—
—
A
A
A
A
A
B
A
B
A
B
C
D
Notes:
Fe = ESF Framing Bits (. . . 001011 . . .)
FDL = 4 kbps Facility Data Link (message bits m)
CRC = CRC-6 Block Check (check bits C1-C6)
Option T = Transparent (bit 8 for traffic)
Option 2 = 2-State Signaling (Channel A)
Option 4 = 4-State Signaling (Channels A, B)
Option 16 = 16-State Signaling (Channels A, B, C, D)
ACST-0351-005
Chapter 1
June 1996
Introduction
1-11