RTS, CTS

From the DTE (Data Terminal Equipment) point of view, you are correct.

From the DCE (Data Communication Equipment) point of view, you got the I/O directions reversed.

One device's input is another's output. One device's output is another's input.

but there should be only one option independant from the point of view because

cts is connected with rts

rts is connected with cts

the left side is according to the pins of the MCU, the right side refers to the interface of peripheral modules. So both point of views dont contradict...

I've got a further question please, which pin function of the MCU should I choose for the cts, rts? The MCLK for the CTS??

thx!

A DTE is supposed to connect to a DCE which "communicates" with another DCE which is connected to the other DTE.

If you want to skip the two DCE's in-between, you use a "Null Modem". A modem is a DCE. A "Null Modem" is equivalent to two DCE's nullifying each other.

The connections you stated is called a "Null Modem" connection. You are looking at RTS and CTS from the DTE point of view on the left. You are looking at the other RTS and CTS from the point of view of the other DTE on the right.

You can use any digital I/O pins of MSP430 for RTS and CTS. The hardware UART in MSP430 does not support them. You use firmware to implement them.

I understand now how the system works, so can I just programm the DTE point of view? Or do I have to choose explicitely the "Null Modem"?

Thanks a lot!

You have two DTE's, thus you have two RTS's and two CTS's  You already inter-connect them through a "Null Modem".