Krzysztof Halasa wrote: > OTOH I wonder what does the device in question require WRT the > serial port and WRT RTS line in particular. > I know there are some half-duplex converters which drive RTS only > while sending and which require CTS to send. As far as I know in the old times this was the *standard* way to use a modem (per CCITT V24), and even nowadays many modems can handle this method for transmit, to stay compatible with the standard. Think of radio modems. Some are inherently half duplex. > They are perhaps a bit broken <snip> No, no, they apply an old standard. Probably they are old as well. > > I don't know if one can expect RTS to stay low all the time. Even > a simple /sbin/setserial from /etc/rc.* would drive it high for > a moment. I'm afraid the only way which makes sense may be using > a customized plug. It's a pity that Linux (or Unixes) never handled RTS this way. I feel that the /proc or sysfs solutions are the best to alter this well established default in this driver. It would not break existing installed hardware. - To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html