When Jack pings back, he may or may not pick up a degree of surprise from the other end of...whatever this is. A moment later, a request is sent back;

Query: ID, purpose

It's not - quite - raw system code. It's a language, in a sense, and there is an actual intelligence on the other end. More than that? Just like speaking a language, one can pick up other things by the way someone is speaking - such as the fact this unit is quite upset with its current situation.