Frame Configuration of 24-DTI
According to the AT&T Specifications for 24-Channel transmission, there are two types of frame
configurations: 12-Multi Frame (D4) and 24-Multi Frame (ESF).
(1) 12-Multi Frame
This configuration has 12-Multi Frames, and each Multi frame has a 24-Channel PCM signal
(8 bits/channel) and a S bit (Super Frame Bit). Figure below shows the frame configuration,
and Table in next page shows frame bit assignment.
CH1
S
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
FRAME 1
125 µs
DTI Frame Configuration (12-Multi Frame)
CH2
CH3
FRAME 2
FRAME 3
DIRECT DIGITAL INTERFACE (DDI)
S: SUPERFRAME BIT
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DTI SPECIFICATIONS
CH24
1 2 3 4 5 6 7 8
FRAME 12
A2195-10