ryushi5

That's great information. Thanks very much! I'll do some experimenting and see where I get.

Are there any alternative methods in BASIC to send serial data?

That's something I was thinking as well. But when I have my o-scope connected, I don't see any attempt for the machine to send a signal. Of course, maybe I'm just missing it.

I'm new to 8-bit machines, and this is my first Coco 2. So far, everything seems to work on the machine as it appears to be in very good condition. The only thing I have found so far is that the large 4700uF cap seems to have leaked a little, and I have a replacement coming for it. Here is what I am having trouble with: I would like to output simple serial communication using the RS-232C port. Nothing complicated, just a few characters. The only way that I have found to do this so far is to print as if to a printer with the command below: PRINT #-2, CHR$(49) Whenever I attempt to print like this, the machine freezes and will not respond to any inputs unless I reset the machine. I have tested the RS-232C output by poking 65312 as suggested in the repair manual. This works, and I get a little less than 5V between GRD and pin 4 on the JK3 port. Any thoughts on what I'm doing wrong?