I know that having TX, RX, GND, RTS, CTS are good. What about all of the others? Do devices these days even make use of the other pins (DSR, RI, DCD, DTR)? Is it safe to generally leave out these pins? It seems to me like these are mostly only used in fully-specified legacy DCE/DTE equipment. FYI I'm asking this question more specifically in the realm of embedded systems, not PCs.