I would like to transfer files (pc -> a500) via null modem cable connected in serial port by using cat command

How to configure serial port for null modem?

The settings I need are below

Baud rate: 19200, bits/char: 8, parity: None, Stop bits: 1, handshaking: RTS/CTS

Welcome to LinuxQuestions.

No configuration is required. A null MODEM is a type of cable.
http://www.camiresearch.com/Data_Com..._standard.html

The stty command will configure the serial port from the command line.
http://tldp.org/LDP/nag2/x-087-2-ser...iguration.html
stty -F /dev/ttyS0 crtscts
stty -f /dev/ttyS0 speed 19200

Thanks for a quick reply!

After studying that link for a moment I guess that the following command captures all those settings I mentioned:

stty 19200 cs8 -parenb crtscts -cstopb -F /dev/ttyS0

(-parenb disbales parity, -cstopb sets one stop bit)

That can be a bit of an over-simplification; yes, a null modem is a kind of cable, but as per the reference that you quote, you can have several different flavours of null modem cables, and if you regard exactly which line gets connected where as configuration (and I don't see a reason, in this context, not to), you would usually expect to select a cable configuration, in combination with the kind of flow control that you use.

Plain command "stty" without any switches or attributes shows the current settings of serial

No matter what form of command I try, I do not manage to switch baud rate. It stays as 38400 whenever I type "stty"

(It seems I have only ttyS0 so the problem is not that I should use ttyS1 or other instead)

Any ideas? Does somebody manage to change his baudrate with stty command so that plain "stty" shows the change?

Use sudo or login as root.

I used debian/lxde's "root terminal" and now also tried by login as root without GUI (what you get by pressing ctrl+alt+F1)

Uhm, the problem is strange indeed.

If you do not use any attributes the results will be the terminal settings and not the serial port. You need specify the serial port device.

Could not get those commands working but I got a better idea: to simply use a terminal program

I actually managed to transfer few lines of typed text which was displayed on Amiga's screen...

But then... DEVICE (ttyS0) which had previously always been shown there simply disappeared from the window of CuteCom (terminal program) and seems not ever return (thus the program "cannot connect")

Perhaps I tried to change speed at that point but returning it does not return ttyS0 to CuteCom's DEVICE slot

Or perhaps I tried setserial command at the moment (though I did not try to change any settings with it)


dmesg | grep ttyS
gives following:
[ 0.914354] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 0.935092] 00:08: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

I guess this output is still the same though I am not dead sure