Reference:ISDN Cause Codes
Summary
H.323 (being based on Q.931 as ISDN is) uses the same cause codes as ISDN does. Such codes can be found in
- traces
- as well as in syslogs and
- call detail records
Note that cause codes are coded differently in traces and syslogs. Here is how to extract cause codes from logs and traces and how they are coded.
Applies To
All innovaphone H.323 products
More Information
How to decode cause codes from traces
Within traces, you will find sequences similar to this:
0:0432:491:0 - TEI0.0 -> Q931.0 : LL_RECV_RESULT data(13),FALC 08 02 80 02 45 08 02 82 81 1e 02 82 88 ....E........
if you have ticked the “trace” checkmark in the “interface configuration”.
Additionally, you will see something like:
0:0432:491:3 - R_CALL.7 -> RELAY.0 : SIG_DISC
CAU = 82 81
if you have ticked the “trace” checkmark in the “protocol configuration”.
In the example, the cause code thus is 82 81.
The first byte (82) gives the Coding-standard and location. It is made up of: bit 8, 7, 6 and 5 usually 1000. Bit 4, 3, 2, 1 gives the location (that is, the entity generating the cause code). If bit 8 to 5 are unequal to 1000, the cause code is non-standard. The location is usually 0010, so that the second byte is usually 0x82 (10000010).
The second byte (81) contains the cause code within the lower 7 bit (1). So you need to clear the MSB to look up the cause code in the table below, using the “Cause (hex)” column. You may also look it up directly using the “Cause, bit 8 set to 1 (hex)” column.
There may be extraneous bytes giving further diagnostic information (Not described here and rarely used).
In the example case, the cause code thus is 0x1, which says “Unallocated number”.
How to decode cause codes from a CDR
CDRs (call detail records) show causes quite similar to the format described for traces, except that the size of the cause code information element is given and that the individual bytes are separated by underscores: cause=02_82_81
How to decode cause codes from a syslog
In a syslog, you will find cause codes for convenience already extracted from the respective information element and coded in decimal:
19700101-000325 CALL 0 B:Disc 32:ckl->00000009 GW1:21->PRI1:0000009: Cause: 1
You can look up the cause code directly in the table below using the “Cause (decimal)” column.
How to decode cause codes from a SIP message
In SIP messages, you may see header lines such as
Reason: Q.850;cause=18
This indicates an ISDN cause code and it is given in decimal, so you can look it up in column 3 of the table below.
What if you don’t find the code
An innovaphone devices only rarely generates cause codes on its own. In normal operation, cause codes are received from the network and blindly output in traces, syslogs and cdr’s. Therefore, you might eventually see cause codes not listed in The table below. Consult the documentation of the cause code generating device to determine their meaning.
Q.931 ISDN Cause Codes
The following table shows the isdn errorcodes according to Q.931:
| Errorcode (hex) | Errorcode, Bit 8 set to 1 (hex) |
Errorcode (decimal) | Meaning |
|---|---|---|---|
| 0x1 | 0x81 | 1 | Unallocated number |
| 0x2 | 0x82 | 2 | No route to specified transit network |
| 0x3 | 0x83 | 3 | No route to destination |
| 0x6 | 0x86 | 6 | Channel unacceptable |
| 0x7 | 0x87 | 7 | Call awarded and being delivered in an established channel |
| 0x10 | 0x90 | 16 | Normal call clearing |
| 0x11 | 0x91 | 17 | User busy |
| 0x12 | 0x92 | 18 | No user responding |
| 0x13 | 0x93 | 19 | No answer from user (user alerted) |
| 0x15 | 0x95 | 21 | Call rejected |
| 0x16 | 0x96 | 22 | Number changed |
| 0x1A | 0x9A | 26 | Non-selected user clearing |
| 0x1B | 0x9B | 27 | Destination out of order |
| 0x1C | 0x9C | 28 | Invalid number format |
| 0x1D | 0x9D | 29 | Facility rejected |
| 0x1E | 0x9E | 30 | Response to STATUS ENQUIRY |
| 0x1F | 0x9F | 31 | Normal, unspecified |
| 0x22 | 0xA2 | 34 | No circuit/channel available |
| 0x26 | 0xA6 | 38 | Network out of order |
| 0x29 | 0xA9 | 41 | Temporary failure |
| 0x2A | 0xAA | 42 | Switching equipment congestion |
| 0x2B | 0xAB | 43 | Access information discarded |
| 0x2C | 0xAC | 44 | Requested circuit/channel not available |
| 0x2D | 0xAD | 47 | Resources unavailable, unspecified |
| 0x31 | 0xB1 | 49 | Quality of service unavailable |
| 0x32 | 0xB2 | 50 | Requested facility not subscribed |
| 0x34 | 0xB4 | 52 | Outgoing calls barred |
| 0x35 | 0xB5 | 53 | Outgoing calls barred within CUG |
| 0x39 | 0xB9 | 57 | Bearer capability not authorised |
| 0x3A | 0xBA | 58 | Bearer capability not presently available |
| 0x3F | 0xBF | 63 | Service or option not available, unspecified |
| 0x41 | 0xC1 | 65 | Bearer capability not implemented |
| 0x42 | 0xC2 | 66 | Channel type not implemented |
| 0x45 | 0xC5 | 69 | Requested facility not implemented |
| 0x46 | 0xC6 | 70 | Only restricted digital information bearer capability is available |
| 0x4F | 0xCF | 79 | Service or option not implemented, unspecified |
| 0x51 | 0xD1 | 81 | Invalid call reference value |
| 0x52 | 0xD2 | 82 | Identified channel does not exist |
| 0x53 | 0xD3 | 83 | A suspended call exists, but this call identity does not |
| 0x54 | 0xD4 | 84 | Call identity in use |
| 0x55 | 0xD5 | 85 | No call suspended |
| 0x56 | 0xD6 | 86 | Call having the requested call identity has been cleared |
| 0x58 | 0xD8 | 88 | Incompatible destination |
| 0x5B | 0xDB | 91 | Invalid transit network selection |
| 0x5F | 0xDF | 95 | Invalid message, unspecified |
| 0x60 | 0xE0 | 96 | Mandatory information element missing |
| 0x61 | 0xE1 | 97 | Message type non-existent or not implemented |
| 0x62 | 0xE2 | 98 | Message not compatible with call state |
| 0x63 | 0xE3 | 99 | Information element non-existent or nor implemented |
| 0x64 | 0xE4 | 100 | Invalid information element contents |
| 0x65 | 0xE5 | 101 | Message not compatible with call state |
| 0x66 | 0xE6 | 102 | Recovery on timer expiry |
| 0x6F | 0xEF | 111 | Protocol error, unspecified |
| 0x7F | 0xFF | 127 | Interworking, unspecified |
Display messages on IP2xx
| Errorcode | German view | English view | français view |
|---|---|---|---|
| 1 | Unbekannte Nummer | number unknown | Numéro inconnu |
| 2 | Keine Verb. zum Netz | no networks access | Pas de liais. réseau |
| 3 | Keine Verb. zum Ziel | no route to dest. | Pas de liais. dest. |
| 4 | sende spez. Inf. Ton | send spec. inf. tone | Tonalité spéciale |
| 5 | falscher Carrier-Code | misdial. trunk prefix | Accès réseau erroné |
| 6 | Kanal nicht akzept. | Channel unacceptable | Canal non dispo |
| 7 | Gespräch schon zug. | call being delivered | Appel en cours achem. |
| 16 | Wahl abgebrochen | Error while dialling | Délai numéro. dépassé |
| 17 | besetzt | subscriber busy | Occupé |
| 18 | Ziel nicht erreicht | no user responding | Aucun poste atteint |
| 19 | keine Antwort | no answer | Pas de réponse |
| 20 | nicht erreichbar | subscriber absent | Pas de réponse |
| 21 | abgelehnt | call rejected | Appel rejeté |
| 22 | Nummer geändert | number changed | Numéro modifié |
| 27 | Ziel nicht bereit | dest. not ready | Destin. non dispo. |
| 28 | Nr. Unvollst./ungült. | incomplete/invalid no | Numéro erroné |
| 29 | Dienst abgelehnt | service rejected | Service refusé |
| 30 | Keine Antw. auf ST. | no response to STATE | STATUT:pas de réponse |
| 31 | Wahl abgebrochen | Error while dialling | Délai numéro. dépassé |
| 34 | Kein Kanal verfügbar | no channel available | Acun canal dispo |
| 38 | Netz nicht bereit | network not ready | Réseau indisponible |
| 41 | temporärer Netzfehl. | temporary failure | Dérangement tempor. |
| 42 | Netz überlastet | network overload | Réseau encombré |
| 43 | Netzinfo gelöscht | access info discarded | Info réseau effacée |
| 44 | Kanal nicht frei | channel not free | Canal non libre |
| 47 | Netz überlastet | network overload. | Réseau encombré |
| 49 | Dienst-Art n. mögl. | service unavail. | Service non dispo. |
| 50 | Dienst n. bekannt | service unknown | Service inconnu |
| 52 | Nummer gesperrt! | Number barred! | Numéro verrouillé! |
| 53 | ausg. gesperrt - CUG | outgoing barred - CUG | Appel externe interdi |
| 54 | eingehend gesperrt | incoming barred | Appel entrant interdi |
| 55 | eing. gesperrt - CUG | incoming barred - CUG | Appel entrant interdi |
| 57 | Dienst unzulässig | service unauthorised | Service non autorisé |
| 58 | Dienst z.Zt n. mögl. | service not available | Service actu. indisp. |
| 62 | ausg. Daten inkosist | inconsist. autg. data | Accés ext. imprécis |
| 63 | Dienst nicht bekannt | service unknown | Service inconnu |
| 65 | Basis-Dienst n. impl | b.-service not impl. | Service non implém. |
| 66 | Kanal-Art nicht impl | ch. type not impl. | Type canal non impl. |
| 69 | Dienst nicht impl. | service not impl. | Service non implém. |
| 70 | nur eingesch. Dienst | only restr. service | Serv. restreint uniq. |
| 79 | Dienst nicht impl. | service not impl. | Service non implém. |
| 81 | falsche Call-Ref | invalid call-ref | Réf. d'appel erronée |
| 82 | falscher Kanal | wrong channel | Canal inexistant |
| 83 | falscher Code | wrong code | Code erroné |
| 84 | Code wird benutzt | code is in use | Code utilisé |
| 85 | keine Verb. geparkt | co call on hold | Pas de com. en att. |
| 86 | Geparkte Verb. ausg. | call has been cleared | Commun. acceptée |
| 87 | nicht Mitglied in CUG | user not a CUG member | Util. non membre CUG |
| 88 | Ziel ist inkompat. | incompatible dest. | Destin. incompatible |
| 90 | CUG existiert nicht | non existent CUG | CUG inexistant |
| 91 | Ungültiges Netz | invalid network | Choix réseau incor. |
| 95 | Fehlerhafte Message | invalid message | Message incorrect |
| 96 | Info-Element fehlt | info element missing | Elém. Info manquant |
| 97 | Message nicht impl. | message not impl. | Message non implém. |
| 98 | Message nicht komp. | message not comp. | Message incompatible |
| 99 | Info nicht bekannt | info unknown | Elém.Info inconnu |
| 100 | Fehlerhafte Info | wrong info | Info incorrecte |
| 101 | Falscher Call-Status | wrong call status | Statut appel erroné |
| 102 | Abbruch nach Timeout | timeout | Délai dépassé |
| 103 | falscher Parameter | wrong parameter | Paramètre inexistant |
| 110 | Daten inkonsistent | inconsistency in data | Données inconstantes |
| 111 | Protokoll-Fehler | protocol error | Erreur protocole |
| 127 | Interworking Fehler | interworking error | Erreur fonctionnement |
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