Wichit Sirichote, email@example.com
Simple hardware expands PC's COM port from COM1 to COM1/1 and COM1/2. No active parts.
I got a problem with my notebook, because it has only COM1. My programmer board, Easy-Downloader must use serial port and the application board also needs to communicate via the same serial port. I do remembered I have to swap DB9 connector of both devices many times. So I spent 30 minutes built above simple hardware. Of course it was not the expander by meaning. But it helps me a lot. Someone may prefer to call it as the rs232 selector, but I like "expander". Above picture is the sample board, no need to make a pcb. You may use universal pcb to make it. Later I will put it in the small plastic box.
27 May 2546
recovered 17 December 2458