Hendrik van Rooyen wrote:
On Saturday 15 August 2009 14:40:35 Michael Ströder wrote:
Hendrik van Rooyen wrote:
In the past, on this group, I have made statements that said that on
Linux, the serial port handling somehow does not allow transmitting and
receiving at the same time, and nobody contradicted me.
Absolutely false.
Despite all the good comments here by other skilled people I'd recommend to
determine whether the transmission line to the devices accessed support
full duplex.
All standard PC serial ports are full-duplex devices.
Here's a program I wrote which uses "pyserial" to drive Baudot teletypes
as full-duplex devices.
https://sourceforge.net/projects/baudotrss/
This uses an input thread and an output thread. It reads RSS feeds and
prints them on antique Teletype machines. (Reuters RSS feeds produce
a classic news ticker. Twitter RSS feeds work but look silly when
hammered out on yellow paper at 45.45 baud.)
You raise a good point, that is probably not well known amongst the youngsters
here, as simple serial multidropping has gone out of fashion.
Actually, no. Dynamixel servos as used on the latest Bioloid robots
are multidrop serial RS-485. But outside the embedded world, nobody uses
that stuff any more. (Embedded is going Ethernet; it's overkill but
works fine and is now cheap.)
John Nagle
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