That reply looks like a TELNET message. The first two characters are ‘Interpret as command’ and ‘DO’, — but I’m not quite sure what it’s asking to ‘do’ — a quick glance at some RFCs doesn’t show what 030 (24) means.
Can you configure your terminal server to 2217 mode, or to ‘raw’ mode? There’s no support in ASYN for a ’TELNET’ terminal server — one that wants to use TELNET commands but doesn’t support RFC 2217.
What is the make and model of your terminal server?
You either need to set the baud and parity with a Web interface or put it in the RFC mode like Eric said and then you can use asynSetOption to set them.