isdn_cause - Description of ISDN cause messages.
DESCRIPTION
This document describes the cause messages, used with the
ISDN D-channel protocols EDSS1 and 1TR6 and their format,
visible to the user.
FORMAT
Cause messages are 2-byte information elements, describing
the state transitions of an ISDN line. Each cause message
describes its origination (location) in one byte, while
the cause code is described in the other byte. Internally,
when EDSS1 is used, the first byte contains the location
while the second byte contains the cause code. When using
1TR6, the first byte contains the cause code while the
location is coded in the second byte. In the Linux ISDN
subsystem, the cause messages visible to the user are uni
fied to avoid confusion. All user visible cause messages
are displayed as hexadecimal strings. These strings always
have the location coded in the first byte, regardless if
using 1TR6 or EDSS1. When using EDSS1, these strings are
preceeded by the character 'E'.
CAUSE MESSAGES WITH EDSS1
LOCATION
The following location codes are defined when using EDSS1:
00 Message generated by user.
01 Message generated by private network serving the
local user.
02 Message generated by public network serving the
local user.
03 Message generated by transit network.
04 Message generated by public network serving the
remote user.
05 Message generated by private network serving the
remote user.
07 Message generated by international network.
0A Message generated by network beyond inter-working
point.
CAUSE
The following cause codes are defined when using EDSS1:
01 Unallocated (unassigned) number.
03 No route to destination.
06 Channel unacceptable.
07 Call awarded and being delivered in an established
channel.
10 Normal call clearing.
11 User busy.
12 No user responding.
13 No answer from user (user alerted).
15 Call rejected.
16 Number changed.
1A Non-selected user clearing.
1B Destination out of order.
1C Invalid number format.
1D Facility rejected.
1E Response to status enquiry.
1F Normal, unspecified.
22 No circuit or channel available.
26 Network out of order.
29 Temporary failure.
2A Switching equipment congestion.
2B Access information discarded.
2C Requested circuit or channel not available.
2F Resources unavailable, unspecified.
31 Quality of service unavailable.
32 Requested facility not subscribed.
39 Bearer capability not authorised.
3A Bearer capability not presently available.
41 Bearer capability not implemented.
42 Channel type not implemented.
45 Requested facility not implemented.
46 Only restricted digital information bearer.
4F Service or option not implemented, unspecified.
51 Invalid call reference value.
52 Identified channel does not exist.
53 A suspended call exists, but this call identity
does not.
54 Call identity in use.
55 No call suspended.
56 Call having the requested call identity.
58 Incompatible destination.
5B Invalid transit network selection.
5F Invalid message, unspecified.
60 Mandatory information element is missing.
61 Message type non-existent or not implemented.
62 Message not compatible with call state or message
or message type non existent or not implemented.
63 Information element non-existent or not imple
mented.
64 Invalid information element content.
65 Message not compatible.
66 Recovery on timer expiry.
6F Protocol error, unspecified.
7F Inter working, unspecified.
CAUSE MESSAGES WITH 1TR6
LOCATION
The following location codes are defined when using 1TR6:
44 Message generated by public network.
45 Message generated by private network.
4F Unknown.
CAUSE
The following cause codes are defined when using 1TR6:
00 Normal call clearing.
01 Invalid Call reference value.
03 Bearer service not implemented.
07 Call identity does not exist.
08 No channel available.
10 Requested facility not implemented.
11 Requested facility not subscribed.
20 Outgoing calls barred.
21 User access busy.
22 Closed user group mismatch.
23 Non existent closed user group.
25 SPV connection not allowed.
35 Destination not obtainable.
38 Number changed.
3A No user responding.
3B User busy.
3D Incoming calls barred.
3E Call rejected.
59 Network congestion.
5A Remote user initiated.
70 Local procedure error.
71 Remote procedure error.
73 Remote user resumed.
7F User info discarded locally.
SEE ALSO
ITU Q.850, FTZ Richtlinien 1TR3, Band 3 (1TR6)
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