ASN.1 schema information is used if one or more ASN.1 schema files are specified on the command- line using the -schema command-line switch. In this case, element names as specified in the schema file are used for the XML element names and the content is decoded based on the specific type.

It is possible to use the –pdu command-line switch to force the association of a type within the specification to the message. This is only necessary if the ASN.1 files contain multiple types with the same start tag as the message type. Otherwise, the program will be able to determine on its own which type to use by matching tags. Note that this is true for BER/DER/CER messages only - for PER, it is necessary to specify the PDU type along with the schema.