I have a couple of Arduino RBBB inits and a 6 pin P4b RS232 to ttl adapter. My computer here has a real 9 pin serial connection..
All works fine using the bub usb to 6 pin at /dev/TTYUSB0 but I can't seem to get the port at /dev/ttyS0 to accept an upload. It does do the reset. So I the port seems to be properly connected. I did uninstall ttybrl. Does anyone have any suggestions
The arduino circuit needs inverters to work with standard RS232 and even then the voltages are sometimes a little suspect. Take a look at the schematic for the Old serial arduinos :
http://webzone.k3.mah.se/k3dacu/arduino/releases/serial_v1/arduino_serial_v1.png
The circuitry at lower left is the inverters for RX and TX.
I have 2 boards, and discovered that. I can't upload to one board serially even if I swap 328 chips. Funny thing is that I can upload just fine using the usb adapter. The second board uploads just fine with the P4b serial adapter, and both boards work well with the serial adapter and the arduino serial monitor.
At any rate what I thought was my OS computer system problem turns out to be my board problem .. think my next step is to inspect with a magnifier and an ohm meter. Wierd problem though.