These messages are issued by the VU Interface if a request cannot be completed for any other reason than the unavailability of the data. These messages are typically the result of a bad request format (Length, SID, ITSID…) but aren't limited to that. The TRTP in the Data Field contains the SID of the request. The Data Field contains a code identifying the reason of the negative answer. The following codes are available:
General Reject (code: 10)
The action can't be performed for a reason which isn't cited below nor in section (Enter DataUnavailable section number).
Service not supported (code: 11)
The request's SID isn't understood.
Sub function not supported (code: 12)
The request's TRTP isn't understood. It can be for instance missing or out of accepted values.
Incorrect message length (code: 13)
The length of the received message is wrong (mismatch between the LEN byte and the actual message length).
Conditions not correct or request sequence error (code: 22)
The required service is not active or the sequence of request messages is not correct
Request out of range (code: 33)
The request parameter record (data field) is not valid
Response pending (code: 78)
The action requested cannot be completed in time and the VU is not ready to accept another request.
ITSID Mismatch (code: FB)
The SRC ITSID doesn't match the associated device after comparison with the Bluetooth information.
ITSID Not Found (code: FC)
The SRC ITSID isn't associated with any device.
Lines 1 through 72 (FormatMessageModule) of the ASN.1 code in Annex 3 specify the messages format as described in table 3. More details about the messages content is given below.