GNT 3601 tape punch docs?

Hi, No, nothing happens. What power supply do you mean? the one of the puncher, yes i think it's ok, cuz as I push one of the buttons of the puncher (the tiny holes puncher and the all holes puncher) it does what it's intended to do. Well, i tried multiple setups, i don't really remember what i did try. About the null modem cable, I wired as follows: 20 DTR - 6 DSR (puncher - puncher) 3 RD (puncher) - 3 TD (PC) 7 Gnd - 5 Gnd 4 DTR - 6 DSR (PC - PC) Note that I didn't try the TX from puncher side, cuz I think it's not returning useful data. Right now, i hooked a led and a resistor to the TX of the PC, I see it flashing as i send some data, then I'll assume the PC is correctly sending. Something comes to my mind, I remember from the days that I programmed PIC MCUs that the serial port of a laptop operates at low voltages, 3V I think. Can it be the problem here? But according to the specifications of the manufacturer, the puncher deals with 3V communication. Hope to get a reply soon, tsch?ss