Again, some basic understanding will go s long way. There are serial handshaking lines that you can query with a VISA property node. You will get asserted, unasserted, or unknown when you query the property. You should know that rs-232 is NOT ttl logic levels.
You've also been told three times now to use an arduino for a ready made solution.
You've also been told three times now to use an arduino for a ready made solution.