Silviu,

First I want to thank you for the effort you are putting into this.
You ARE helping me out. and ... I really did take the challenge to implement a modem emulation in a 8052, and it is actually working ok ... which makes me the slave he? :)
(check my user page here at 8052.com for more on this)
Fact is that this emulation doesn't support DTR, DSR, RTS or CTS yet, and I want to implement it.

The principle of DTR and DSR use are clear to me now.
I also understand that RTS and CTS are NOT cross linked.

From now on, let's have in mind that the DCE (modem) already acknowledged the DTE's (computer) active DTR with a raised DSR and that this status is held.

I tried to compile your explaination in two simple rules:

- when RTS is low, both DTE and DCE must cease transmission
- when CTS is low, only DTE must cease transmission

is this correct?
does the computer stop interpreting data from the modem when RTS is dropped?


kind regards,

Joachim.