M.Kok

Hello, I have a single V570 and a circuit board. I want to communicate via RS485 with my circuit board. I use hyperterminal to check the communication. via rs232 everything works fine. when i change my settings to RS485 i receive some of the send messages and then it stops. sometimes it continues but is unpredictable. I tried termination on and off but only off works. I tried different speed but It works with 19200 so I do not think that this is the problem. any suggestions? when i use hyper terminal as my input to the circuit board everything works fine too. I send a message and i receive a massage back.