ISDN Diagnostic Codes See also: Error Messages - Main Menu Cause Code (Dec) Value in trace (Dec) Cause Code (Hex) Value in trace (Hex) Meaning Category 0 - normal event 00 128 00 80 Normal Disconnect 01 129 01 81 Unassigned (Unallocated number) 02 130 02 82 No route to specified transit network 03 131 03 83 No route to destination 04 132 04 84 Send special information tone* 05 133 05 85 Misdialled trunk prefix* 06 134 06 86 Channel unacceptable 07 135 07 87 Call awarded and being delivered in an established channel 08 136 08 88 Preemption* 09 137 09 89 Preemption, circuit reserved for re-use* Category 1 - normal event 16 144 10 90 Normal call clearing 17 145 11 91 User busy 18 146 12 92 No user responding 19 147 13 93 User alerting, no answer 20 148 14 94 Subscriber absent* 21 149 15 95 Call rejected 22 150 16 96 Number changed 23 151 17 97 Redirection to new destination* 24 153 19 99 Exchange routing error* 26 154 1A 9A Non-selected user clearing 27 155 1B 9B Destination out of order 28 156 1C 9C Invalid number format 29 157 1D 9D Facility rejected 30 158 1E 9E Response to STATUS ENQUIRY 31 159 1F 9F Normal unspecified Category 2 - resource unavailable 34 162 22 A2 No circuit/channel available 38 166 26 A6 Network out of order 39 167 27 A7 Permanent frame mode connection out of service* 40 168 28 A8 Permanent frame mode connection operational*
41 169 29 A9 Temporary failure 42 170 2A AA Switching equipment congestion 43 171 2B AB Access information discarded 44 172 2C AC Requested circuit/channel not available 46 174 2E AE Precedence call blocked* 47 175 2F AF Resource unavailable, unspecified Category 3 - service or option not available 19 177 31 B1 Quality of service unavailable 50 178 32 B2 Requested facility not subscribed 53 181 35 B5 Outgoing calls barred within CUG* 55 183 37 B7 Incoming calls barred within CUG* 57 185 39 B9 Bearer capability not authorized 58 186 3A BA Bearer capability not presently available 63 191 3F BF Service or option not available, unspecified Category 4 - service or option not implemented 65 193 41 C1 Bearer capability not implemented 66 194 42 C2 Channel type not implemented 69 197 45 C5 Requested facility not implemented 70 198 46 C6 Only restricted information bearer capability available 79 207 4F CF Service or option not available, unspecified Category 5 - invalid message (e.g. parameter out of range) 81 209 51 D1 Invalid call reference value 82 210 52 D2 Identified channel does not exist 83 211 53 D3 A suspended call exists, but this identity does not 84 212 54 D4 Call identity in use 85 213 55 D5 No call suspended 86 214 56 D6 Call having the requested call identity has been cleared 87 215 57 D7 User not a member of CUG* 88 216 58 D8 Incompatible destination 90 218 5A DA Non-existent CUG* 91 219 5B DB Invalid transit network selection 95 223 5F DF Invalid message, unspecified Category 6 - protocol error (e.g. unknown message) 96 224 60 E0 Mandatory Information Element is missing 97 225 61 E1 Message type non-existent or not implemented 98 226 62 E2 Message not compatible with call state, or not implemented 99 227 63 E3 Information Element non-existent or not implemented
100 228 64 E4 Invalid Information Element contents 101 229 65 E5 Message not compatible with call state 102 230 66 E6 Recovery on time expiry 103 231 67 E7 Parameter not implemented* 111 232 6F EF Protocol Error, unspecified Category 7 - interworking 127 255 7F FF Interworking, unspecified Extracting ISDN Cause Codes from a trace See also: Introduction to DiTrace - please read this first ISDN cause codes ISDN location codes When using ISDN, it is useful to be able to interpret the information returned by RELEASE and DISCONNECT frames, since this gives the reason that a call has been disconnected or refused. You see the DISCONNECT or RELEASE frames in one of two situations: 1. When a call SETUP has been issued, the device at the other end (or the network itself) can refuse to connect the call by sending DISCONNECT or RELEASE. 2. When a call is already connected (i.e. the SETUP was met with a CONNECT message, and a pointto-point connection is now established), then either party can end the call by sending a DISCONNECT. Also, the network itself might end the connection (for example, if some network equipment fails or the network becomes congested). The information that we are interested in is coded in an 'information element' present on RELEASE, DISCONNECT and STATUS messages called 'cause'. The whole information element consists of 4 bytes; for instance: 08 02 82 BF The "08" means "Cause" and the "02" means that two further bytes of information follow. So, the 'cause' is '82 BF'. These further two bytes break down into bit fields as follows: 7 6 5 4 3 2 1 0 +----+----+----+----+----+----+----+----+ 1 Coding 0 Location +----+----+----+----+----+----+----+----+ 1 Cause Value +----+----+----+----+----+----+----+----+ The Coding field gives the Coding Standard, showing what standard you need to refer to in order to understand the Cause Value. Generally, coding standard will be "00" means CCITT standard, which is also used for the ETSI standard (EuroISDN). For completeness, Coding Standard field can be one of the following: 00 CCITT standardized 01 reserved for national standards 10 national standard 11 standard specific to identified location The Location field shows who issued this diagnostic code. This is useful information where the two communicating devices are on different ISDN networks (perhaps with one or more transit networks between), or are using ISDN though private network such as a PABX. The possible location codes are:
Binary Hex Value in trace 0000 0 80 user Meaning 0001 1 81 private network serving the local user 0010 2 82 public network serving the local user 0011 3 83 transit network 0100 4 84 public network serving the remote user 0101 5 85 private network serving the remote user 0111 7 87 international network 1010 A 8A network beyond interworking point More information on what these codes mean In the example trace above, value for this byte is 0x82 (in binary this is 1000 0010), so we can break this down as follows: 1000 0010 1...... This bit is always 1..00.... Coding Standard = CCITT...0... This bit is always 0.... 0010 Location is "public network serving the local user" The Cause Value field is where the diagnostic code itself appears. Note that the top bit is always set, so in fact we only need to look at the lower 7 bits when we look up this value. In the example above, we have the value 0xBF which decodes as follows: 1011 1111 1...... This bit is always 1..011 1111 Code is 0x3F (63 in decimal) which means "Service or option not available, unspecified". When we interpret the value 0x3F, we know that we use the CCITT list because the Location field (in the previous byte) told us so. In fact there is more information that we can get from the Cause code because the first three bits give a general category of error, and the last four bits give the error within the category. The categories are: 000 normal event 001 normal event 010 resource unavailable 011 service or option not available 100 service or option not implemented 101 invalid message (e.g. parameter out of range) 110 protocol error (e.g. unknown message) 111 interworking So the breakdown of code 0xBF is actually as follows: 1011 1111 1...... This bit is always 1..011... Category is "service or option not available"...1111 Code is 0xF in category 3, "Service or option not available, unspecified". Line Check Errors See also: Error Messages - Main Menu About Line Check
Success! Line Check test passed Failure! No ISDN card found. DIVA software not correctly installed Failure! ISDN card does not work correctly. Installation probably not correct Failure! Unknown error. A resource conflict probably exists in your system or the DIVA card has been removed Failure! Test aborted with an error - Layer 1 error. Check cable/nt! - TEI Error - Layer 2 error Failure! Unknown error. Please contact support Success! Line Check test passed. This is the successful (and desired) outcome of the Line Check test. It indicates that the DIVA card is installed correctly and is communicating with the network. This is not an exhaustive test and does not necessarily mean that all calls placed through the card will always work. Failure! No ISDN card found. DIVA software not correctly installed. This Line Check utility is unable to locate any DIVA card in your system. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! ISDN card does not work correctly. Installation probably not correct. The Line Check utility has located a DIVA card on your system, but is unable to communicate with it. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! Unknown error. A resource conflict probably exists in your system or the DIVA card has been removed. The Line Check utility has located a DIVA card on your system, but is unable to communicate with it. This is probably due to a conflict with other devices in your computer. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! Test aborted with an error. The message will report some additional information: Layer 1 error. Check cable/nt! Check that the cable is plugged into the DIVA card. In the case of a DIVA Server 4BRI, check that the cable is
connected to the port that you are testing. Beware if you have LAN adapter in your PC that you have not connected the ISDN line to this card. TEI Error. Repeat the test. If the problem is persistent, you may need to change the card configuration to match your ISDN line. Layer 2 error. Repeat the test. Some ISDN switches are sensitive to equipment being unplugged and will cause this error. If the problem is persistent, this needs in-depth analysis using the DiTrace tool. Use this link for Windows 95/98 and this link for Windows NT. Failure! Unknown error. Please contact support. Internal Line Check error. Location codes See also: Diagnostic codes Extracting 'Cause' information from a trace MDL Errors Error Messages - Main Menu An ISDN Cause code consists of 2 bytes; the first byte contains the 'location' code (with some other information) and the second byte contains the diagnostic code. The Location field shows who issued the diagnostic code. This is particularly useful information where the two communicating devices are on different ISDN networks (perhaps with one or more transit networks between), or are using ISDN though a 'private network' such as a PABX. The possible location codes are: Location code (Hex) Value in trace 0 80 user Meaning (Click on a link below to highlight the component) 1 81 private network serving the local user 2 82 public network serving the local user 3 83 transit network 4 84 public network serving the remote user 5 85 private network serving the remote user 7 87 international network A 8A network beyond interworking point
MDL Errors See also: Diagnostic codes Location codes Extracting 'Cause' information from a trace Other errors The following table shows errors reported by the MDL-ERROR-INDICATION primitive to do with layer- 2 establishment on the "D" channel. MDL is the standard prefix for messages to do with communication between layer management and the data link layer. In a DIVA trace, these codes appear in messages 'MDL-ERROR(x)', where 'x' is one of the following error codes. Error Code Error Condition Action Error Type A Supervisory (F=1) Error Log Receipt of unsolicited B DM (F=1) Error Log Receipt of unsolicited C UA (F=1) TEI removal procedure or TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure D UA (F=0) TEI removal procedure or TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure Receipt of unsolicited Receipt of unsolicited E DM (F=0) Error Log Receipt of unsolicited F SABME Error Log Peer initiated re-establish. G SABME TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal Unsuccessful retransmission (N200 times)
procedure H DISC TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure Unsuccessful retransmission (N200 times) I Status Enquiry Error Log Unsuccessful retransmission (N200 times) J N(R) error Error Log Other K Receipt of FRMR Error Log Other L M N Receipt of frame with undefined control field Receipt of I field not permitted Receipt of frame with wrong size Error Log Error Log Error Log Other Other Other O N201 error Error Log Other Adapted from ETS 300 125.