On 28 Dec 2019 at 18:11, tom ehlert wrote: > >When I couldn't get a reading on my scope I decided a more direct approach > >by piping direct from > the console: > >ECHO TEST>COM1 > > good idea. unfortunately this only works with proper DTR/CTS/RTS/... status > lines > connected. > > > Tom
Matt if you're conversant with an oscilloscope, I suspect it shouldn't be a problem for you to pull the CTS, DCD and DSR into a happy signal level, right? See their respective polarities: http://www.larvierinehart.com/serial/serialadc/serial.htm#8 I believe this should be read as: All the CTS, DCD and DSR are "active low" at the TTL level. But, as the RS232 line transceiver chips (level shifters) are inverting, at the RS232 levels the signals are actually active high...? I.e., pulling all three of them to +5V against GND should do the job. I.e., pull the three of them high, and send some data down COM1, and you should get something out the TX line. Frank Rysanek _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
