User guide

46 RealCT Direct API Developer Guide
Chapter 3: T1 Networking
Figure 12 shows a single timeslot within an ESF superframe.
Each timeslot in the superframe follows the same pattern for
signaling bits.
Figure 12. An ESF Superframe
T1 devices support both D3/D4 and ESF framing. Be sure your
application uses the same framing method as your carrier.
Using the wrong framing method causes the two ends not to
synchronize.
Data
Data
CRC
0 1 2 3 4 5 6 7
0
0
Data
Data
CRC
0
Data
Data
CRC
1
Data
Data
CRC
0
Data
Data
CRC
1
Data
Data
CRC
1
1
2
3
4
5
A
B
C
DD
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
F
Bits in timeslot 0
Frame
number
Through timeslot 23
C