The purpose of the Signal information element is to allow the network to optionally convey information to a user regarding tones and alerting signals. (See 7).
The Signal information element is coded as shown in Figure 4-34 and Table 4-24.
The length of this information element is three octets.
The Signal information element may be repeated in a message.
Bits |
||||||||
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
Octets |
Signal Information element identifier |
||||||||
0 |
0 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
Length of signal contents |
||||||||
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
2 |
Signal value |
3 |
|||||||
Signal information element
Signal information element
Signal value (octet 3) |
|
Bits |
|
8 7 6 5 4 3 2 1 |
|
0 0 0 0 0 0 0 0 |
Dial tone on |
0 0 0 0 0 0 0 1 |
Ring back tone on |
0 0 0 0 0 0 1 0 |
Intercept tone on |
0 0 0 0 0 0 1 1 |
Network congestion tone on |
0 0 0 0 0 1 0 0 |
Busy tone on |
0 0 0 0 0 1 0 1 |
Confirm tone on |
0 0 0 0 0 1 1 0 |
Answer tone on |
0 0 0 0 0 1 1 1 |
Call waiting tone |
0 0 0 0 1 0 0 0 |
Off-hook warning tone |
0 0 0 0 1 0 0 1 |
Preemption tone on |
0 0 1 1 1 1 1 1 |
Tones off |
0 1 0 0 0 0 0 0 |
Alerting on - pattern 0 (Note 1) |
0 1 0 0 0 0 0 1 |
Alerting on - pattern 1 (Note 1) |
0 1 0 0 0 0 1 0 |
Alerting on - pattern 2 (Note 2) |
0 1 0 0 0 0 1 1 |
Alerting on - pattern 3 (Note 1) |
0 1 0 0 0 1 0 0 |
Alerting on - pattern 4 (Note 1) |
0 1 0 0 0 1 0 1 |
Alerting on - pattern 5 (Note 1) |
0 1 0 0 0 1 1 0 |
Alerting on - pattern 6 (Note 1) |
0 1 0 0 0 1 1 1 |
Alerting on - pattern 7 (Note 1) |
0 1 0 0 1 1 1 1 |
Alerting off |
All other values are reserved. |
|
NOTES 1. The use of these patterns is network dependent. 2. Used for special/priority alerting. |
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