Hello,
I'm trying to connect my PC to a multimeter (Gossen Metratop 53) via a RS232 interface.
I'm using a generic COM port of my mainboard with an 1:1 pinout cable to the multimeter. The device has a female DB9 connector.
So there shouldn't be any problem with a direct connection without a null-modem cable or a crossover cable, right?
In the manual of the multimeter the pinout isn't mentioned (
pdf manual).
I already tried the connections in the picture:

.
There isn't any response at all. The status of the input lines of the connection are seen in the attached picture.
If I'm using an USB-RS232 adapter cable, at least I can receive some data from the meter (IDN after every change in the interface option), but I can't send anything because the adapter outputs only TTL voltages.
Obviously the baud rate, parity, number of data bits and stop bits are for both devices the same (19200, N, 8, 1).
Do you have an idea what could be wrong? Because I'm quite sure I'm doing something wrong.
Thanks for your help.
Best regards
Momchilo