CP340 pinout configuration

I've got a small project to change a CP340 connection from a MDS radio to a Moxa 3170.

I have tried to connect directly with a serial ported Modscan to no avail. The station is 95, 4800, 8n1, ASCII

Do I need to also connect DTR/CTS etc.? I have a simple null modem cable made using the standard 2,3, & 5. The manual says this is workable, but also shows the DTR and others talking?

Thanks for forum!