Creating a New
Binary Message Using an ASN.1 Schema
A new empty message can be created by using an ASN.1
schema file as the template using the Empty Message
command.
1. Click the File option from the File
Operations toolbar.
2. Select the New Message > Empty
Message option to open an Empty Message creation
wizard (Ctrl + E for a shortcut):
The toolbar icon can also be used:
3. The Create Empty ASN.1 Message
Wizard dialog window will be displayed:
This dialog will present two types of ASN.1 Standard
Categories to choose from:
- 1997 / 2001
ASN.1 Standard: this option will
be selected by default.
- 1990
ASN.1 Standard:
if ASN.1 files are using MACRO definitions, then this
option should be selected.
It will also ask for selection of the ASN.1 encoding rules to be used:
- BER/DER - for the Basic or Distinguished Encoding Rules
- PER (aligned) - for the Packed Encoding Rules, aligned variant
- PER (unaligned) - for the Packed Encoding Rules, unaligned variant
4. The Add button next to the ASN.1 Files selection box will allow the user
to add the ASN.1 files required to create a new message. The Add button next to the Include Directories selection box allows specification of include directories for specifications that import items from other ASN.1 specifications.
5. After adding at least one ASN.1 schema file, the Next button will be enabled. ASN1VE will then try to compile the selected ASN.1 files. If the ASN.1 files have syntax errors, then the following
dialog window will be displayed:
Pressing the OK button will dismiss the window. Details on the specific errors are output to the error log window in the lower right area of the display:
The user must then correct the syntax errors in the ASN.1 file and then the operation may be retried.
If the validation is successful, then the following
dialog window will be displayed:
6. In this step, Display Possible PDU Types
and Display All Types radio boxes will
be displayed with the list of module names in the selected
ASN.1 specifications. Each module will contain a list
of type names in that module.
The Display Possible
PDU Types button selection will show only those
types that are most likely to be used for a new message.
This is defined to be all types in the module that are
not referenced by any other types. If no types meet this
criteria, then no types will be displayed in that module's
type list.
The Display All Types
selection will display all of the types for
each module.
Note: The
Finish button will be enabled after selecting
the PDU type. On pressing this button, ASN1VE will create
a new message using the selected PDU type with all data
values set to empty (zero) or to any default values defined in the schema. In the case of PER, elements that have constraints will be set to a value within the constraint range. The message view will be switched
to element view and that will allow the user to start
message editing and to populate the fields with data.
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