Figure 1-4. D4 Format and Channelization
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
1
0
0
0
1
1
0
1
1
1
0
0
1
0
0
0
1
1
0
1
1
1
0
0
FS
F
T
Combined F
Frame #
1 Superframe = 12 Frames
1.5 milliseconds, 2316 bits
125 microseconds, 193 bits
1 Frame
F 1
2
3 4
5
6
7
8
F 1
2
3 4
5
6
7
8 1
2
3 4
5
6
7
8
1
2
3
4
5
6
7
8
Bit 3
Channel #
1
2
24
Frame
#
1
2
3
4
5
6
7
8
9
10
11
12
1
0
0
0
1
1
0
1
1
1
0
0
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
A
V
V
V
V
V
B
A Signaling Frame
B Signaling Frame
8-Bit Voice
8-Bit Voice
7-Bit Voice
7-Bit Voice
F = Framing (overhead) bit
V = Bit used for voice code
A = Primary signaling bit
B = Secondary signaling bit
Chapter 1
ACST-0351-005
Introduction
June 1996
1-10