Roger Meier's Forums

I was trying to use CoolTerm yesterday to send and receive short HEX data between my OS X 10.8.2 laptop and my TV set through a USB to RS-232 adapter.

I was able to receive data from the TV as expected. When I tried to send a HEX series of seven bytes using the 'Send String' window, I didn't get any response from my TV as expected and the CoolTerm TX indicator remained off.

In the main CoolTerm window I could type a few characters and would see the TX indicator light as expected. I just can't send the required special characters / codes.

I am able to send and receive correctly using a python script on the same hardware and using a similar app "Free Serial Port Monitor"in Windows 7.
So, I'm wondering if Send String is broken when run on OS X 10.8?

Great utility I'll be looking forward to using on future projects.

Thanks for your feedback. I tested 'Send String' under OS 10.8.2 and it works as it should. Something else must be afoot.

A simple thing you can try is to loopback the transmitted data by connecting pins 2 and 3 together on the 9-pin connector of your RS-232 interface. By doing this, you should receive everything that is being transmitted. If you are using non-printable HEX characters, use the Hex view to look at the received data. It should match what is being sent.

I hope this helps.

That the TX indicator doesn't always flash when using 'Send String' stems from the fact that the terminal window is not the active window in that case and less priority is given by the OS to refresh its contents. By the time the OS spends a cycle to refresh the window, the transmission may already be over and the status of the TX indicator has already been reset. if you enter longer strings in the 'Send String' window that take a little longer to write to the buffer you can manage to get the TX indicator to flash.