Specifications
Introduction
1-14 MP2100M-LS-2 Modules - Installation and Operation Manual
T - Housekeeping Byte
S - Framing Byte
LEGEND
Substructure No.1
2
20
38
56
72
71706968676665646355 57 58 59 60 61 62
54
5352515049
4847
4645
37 39
40 41 42 43 44
36
35343332313029282719 21 22 23 24 25 26
8765431 9 10 11 12 13 14 15 16 17
18
T1S1
S2 T2
S3 T3
S4 T4
A1 B1 C1 D1 E1 F1 B2 A2 D2 C2 F2 E2 A3 B3 C3 D3 E3 F3
E2F2C2D2A2B2F1E1D1C1B1A1E4F4C4D4A4B4
A3 B3 C3 D3 E3 F3 B4 A4
D4
C4 F4 E4 A1 B1 C1
D1
E1 F1
E4F4C4D4A4B4F3E3D3C3B3A3E2F2C2D2A2B2
Substructure No.2
Substructure No.3
Substructure No.4
Figure 1-10. Structure of ITU-T Rec. X.58 Signal
The user envelopes are assigned as follows:
• A 2.4 kbps user channel uses three envelopes out of every 80, and thus
appears three times per structure (the envelopes identified by the same
letter/numeral combination, e.g., one 2.4 kbps channel in all the A1
envelopes, another in all the B1 envelopes, etc.). Therefore, the maximum
number of 2.4 kbps channels that can be carried by one main link time slot
is twenty-four: this requires a group of four LS-2/X.58 modules.
• A 4.8 kbps user channel uses six envelopes out of every 80, and thus
appears six times per structure (the envelopes identified by the same letter,
and an odd or even numeral, e.g., one 4.8 kbps channel in all the A1+A3
envelopes, another in all the A2+A4 envelopes, etc.). Therefore, the
maximum number of 4.8 kbps channels that can be carried by one main link
time slot is twelve: this requires a group of two LS-2/X.58 modules.
• A 9.6 kbps user channel uses twelve envelopes out of every 80, and thus
appears twelve times per structure(the envelopes identified by the same
letter, e.g., one 9.6 kbps channel in all the A envelopes, another in all the B
envelopes, etc.). Therefore, the maximum number of 9.6 kbps channels that
can be carried by one main link time slot is six.
• A 19.2 kbps user channel uses twenty-four envelopes out of every 80, and
thus appears twenty-four times per structure, i.e., at twice the rate of the
9.6 kbps channels, by using envelopes pairs (A and D, B and E, or C and F).
Therefore, the maximum number of 19.2 kbps channels that can be carried by
one main link time slot is three.
AT&T Pub. 54075 (DS0-B) Multiplexing Format
The multiplexing format specified by AT&T Pub. 54075 is similar to the
multiplexing format of ITU-T Rec. X.50. Therefore, the multiplexing format
presented in figures 1-7 and 1-9 also defines the multiplexing capabilities of an
LS-2/X.50 module.
The main differences are as follows:
• Referring to figure 1-7, the eighth bit in each byte serves as a network