The purpose of the Call state information element is to describe the current status of a call, (see 2.1) or an access-connection (see 2.2) or a global interface state (see 2.4).
The Call state information element is coded as shown in Figure 4-13 and Table 4-8.
The length of this information element is three octets.
Bits |
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8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
Octets |
Call identity information element identifier |
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0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
Length of call identity contents |
2 |
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Call identity (any bit pattern allowed, e.g. IA5 characters) |
3 etc. |
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Call identity information element
Bits |
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8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
Octets |
Call state information element identifier |
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0 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
Length of call state contents |
2 |
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Coding |
Call state value / global interface state value |
|
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Call state information element
Call state information element
Coding standard (octet 3) |
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Bits |
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8 7 |
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0 0 |
CCITT standardized coding, as described below |
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0 1 |
ISO/IEC standard (Note) |
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1 0 |
National standard (Note) |
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1 1 |
Standard defined for the network (either public or private) present on the network side of the interface (Note) |
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Note - These other coding standards should only be used only when the desired call states cannot be represented by CCITT-standardized coding. |
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Call state value (octet 3) |
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Bits |
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6 5 4 3 2 1 |
User State |
Network state |
0 0 0 0 0 0 |
U0 - Null |
N0 - Null |
0 0 0 0 0 1 |
U1 - Call initiated |
N1 - Call initiated |
0 0 0 0 1 0 |
U2 - Overlap sending |
N2 - Overlap sending |
0 0 0 0 1 1 |
U3 - Outgoing call proceeding |
N3 - Outgoing call proceeding |
0 0 0 1 0 0 |
U4 - Call delivered |
N4 - Call delivered |
0 0 0 1 1 0 |
U6 - Call present |
N6 - Call present |
0 0 0 1 1 1 |
U7 - Call received |
N7 - Call received |
0 0 1 0 0 0 |
U8 - Connect request |
N8 - Connect request |
0 0 1 0 0 1 |
U9 - Incoming call proceeding |
N9 - Incoming call proceeding |
0 0 1 0 1 0 |
U10 - Active |
N10 - Active |
0 0 1 0 1 1 |
U11 - Disconnect request |
N11 - Disconnect request |
0 0 1 1 0 0 |
U12 - Disconnect indication |
N12 - Disconnect indication |
0 0 1 1 1 1 |
U15 - Suspend request |
N15 - Suspend request |
0 1 0 0 0 1 |
U17 - Resume request |
N17 - Resume request |
0 1 0 0 1 1 |
U19 - Release request |
N19 - Release request |
0 1 0 1 1 0 |
- - - - - - |
N22 - Call abort |
0 1 1 0 0 1 |
U25 - Overlap receiving |
N25 - Overlap receiving |
Global interface state value (octet 3) |
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Bits |
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6 5 4 3 2 1 |
State |
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0 0 0 0 0 0 |
REST0 - Null |
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1 1 1 1 0 1 |
REST1 - Restart request |
|
1 1 1 1 1 0 |
REST2 - Restart |
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All other values are reserved. |
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