PDUs (Protocol Data Units) are units used to transmit data through PETEP. They contain operational data (tags, destination, connection, ...), data bytes and sometimes also protocol-specific data.
PDUs can be tagged using tags to distinguish PDUs between each other. Using tags, you can for example differentiate specific message and then perform some operation on it (f.e. replacement).
PETEP has built-in editor of PDUs, that is divided into two sections - PDU flow and PDU data.
PDU flow contains configuration of internal flow:
PDU data contains configuration of tags, data and it might also contain protocol-specific configuration.
You can change charset of the displayed data by clicking on the charset in the bottom right corner of the data editor.
It is highly recommended to use charset ISO-8859-1 for unknown data, because it represents the whole byte range (0-255) and prevents encoding problems.
You will came across serialized PDU view in case that PETEP core is inactive or when PDU is broken. It contains serialized PDU to plain-text displayed in text inputs.