Serial Port Downloads to 41CL

[aurelio]

I've tried to install it with care, and hope to have not damaged plug or slot while doing it.
But if I'm not systematically wrong I'm pretty sure of that,
I got the same result with two different machines so that before to opening the calculator I'll try at least with the V4 to create a loopback connection at the DB9 end of the serial cable and following steps as suggested by Monte

First of all I've checked the factory made cable one more time, who knows?
it's OK
2-tip
5-ring
3-shield
then
7-8 loop (*)
4-6 loop (*)
pins 4 to 6 and 7 to 8 are looped I suppose for RTS/CTS hardware flow control and for DTR/DSR hardware flow control emulation when needs (not our case).

then loopback procedure will follow....

edit: factory serial cable DB9-stereo jack checking