On Tue, Jan 26, 2021 at 5:30 AM Stuart Longland <stua...@longlandclan.id.au> wrote: > > On 25/1/21 11:40 pm, Bastien Durel wrote: > > Hello, > > > > Short-circuit pins 3-5 using my DB9 cable as Mihai Popescu said[1] > > worked. > > Alas, this setup prevent to plug-in the cable on the other side ^^ > > > > But this confirm there is an hardware problem.
The issue is the input RCV line is floating which causes spurious characters, a properly designed circuit should not have this issue. You really should insert a high ohm valu resistor in the path between RCV and GND, this would allow you to build a serial cable that still functions.