I do not have a modem, but even if i would have one, i could not transfer the disk images, because the modem connects the Atari computer and the pc together and without the dos disk, i could not write anything to disk with the computer.
I need to connect the Atari 1050 directly to the pc and write the disk image out.
The SIO2PC page says i could do it with a cable named "1050-2-PC", but i do not know, where can i get one.