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CDM-600L Satellite Modem
Clock Modes and Drop and Insert (D&I)
10.4
Drop and Insert
The Drop and Insert multiplexer works in conjunction with the G.703 interfaces to enable
the modem to transmit or receive fractional parts of a T1 or E1 data stream.
The D&I option provides fully compliant baseband processing in accordance with
Intelsat IESS
(T1), using G.703 interfaces. The data rate sent over the satellite link is n x 64 kbps. See
the Frame Formats diagram for the permissible values of n. The modem provides the
interface to transmission level framing compliant to IESS
Note: For Hardware Version 2.0 or higher, D&I operation is possible through the 25-pin
data port in either RS-422 or V.35 format. If used, the DDO/IDI 'inner loop' is not
available.
For Firmware Version 1.2.0 or higher, D&I operation can also be done using the
proprietary D&I++ framing mode.
10.5
Frame Formats
The E1 and T1 frame formats that are supported are shown in the Figure below:
E1-CCS (Common Channel Signalling)
2048 kbps E1 Frame
1
2
Time
0
1
2
Slot
No.
Reserved for
Framing
E1-CAS (Channel Associated Signalling)
2048 kbps E1 Frame
1
2
Time
0
1
2
Slot
No.
Reserved for
Framing
T1-ESF (Extended Super Frame)
1544 kbps T1 Frame
Maximum channels to drop = 24 = 1536 kbps n x 64 kbps, n = 1,2,3,4,5,6,8,10,12,15,16,20,24
1
2
3
Time
1
2
3
Slot
No.
T1-D4 (D4 Framing)
1544 kbps T1 Frame
Maximum channels to drop = 24 = 1536 kbps n x 64 kbps, n = 1,2,3,4,5,6,8,10,12,15,16,20,24
1
2
3
Time
1
2
3
Slot
No.
308 for the terrestrial information rate of 2048 kbps (E1) and 1544 kbps
-
Maximum channels to drop = 30 = 1920 kbps
3
4
5
6
7
8
9
10 11 12
3
4
5
6
7
8
9
10 11 12
Maximum channels to drop = 30 = 1920 kbps
3
4
5
6
7
8
9
10 11 12
3
4
5
6
7
8
9
10 11 12
24-Frame multi-frame structure. No IBS multi-frame signalling will be transmitted.
4
5
6
7
8
9
10 11 12 13
4
5
6
7
8
9
10 11 12 13
12-Frame multi-frame structure. No IBS multi-frame signalling will be transmitted.
4
5
6
7
8
9
10 11 12 13
4
5
6
7
8
9
10 11 12 13
Figure 10-3 Supported T1 and E1 Framing Formats
n x 64 kbps, n = 1,2,3,4,5,6,8,10,12,15,16,20,24,30
13
14
15
16
17
18 19 20 21
13
14
15
16
17
18
19 20 21 22
May be reserved for Signalling. All signalling
information is common to all 30 TS and no signalling is
transmitted.
n x 64 kbps, n = 1,2,4,6,8,12,16,24,30
13
14
15
16
17
18 19 20 21
13
14
15
16
17
18
19 20 21 22
Reserved for Signalling. All signalling is transmitted
for TS's dropped in IBS overhead (500Hz per TS)
Signalling information in TS 16 is associated to
specific TS's.
14
15
16
17
18
19
20 21 22 23
14
15
16
17
18
19
20 21 22 23
14
15
16
17
18
19
20 21 22 23
14
15
16
17
18
19
20 21 22 23
10–6
MN/CDM600L.IOM
309 data type 2.
-
22
23
24
25
26
27
28
29
23
24
25
26
27
28
29
30
22
23
24
25
26
27
28
29
23
24
25
26
27
28
29
30
24
24
24
24
Revision 2
30
31
30
31
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