Hello!

first of all I am not sure if this is the right place to post this so apologies if it isnt and ill delete it.

I recently gotten a vintage HP draftpro DXL 7575A plotter and ive been trying to get it to work on my windows 10 machine.
It has a serial RS-232-C port on the back and im using a serial rs-232 to usb converter to connect it to my PC.
But when i use the terminal to send commands I receive nothing.

I installed and reinstalled the drivers of the converter. and confirmed it worked because i shorted the RX and TX pin and i got a feedback loop.
The plotter itself also isnt the problem because everything on it works. the demo plot works fine and so do all the buttons.

so it must be a connection problem. and thats where im stuck.

the code im sending is HPGL which is easy to send a few commands.

the code:
IN;
SP1;
PA2000,2000;
CI500;

which means it initialises the plotter, picks pen 1, goes to coordinates 2000,2000 and draws a circle.

I checked the manual if i put the DIP switches in the right spot and the BAUD rate is correct

manual: HP Computer Museum

I also added some pictures of the back and the cable im using.

Thanks for reading all of this!
Damnub