MCR_CTS
sc->sc_msr = sc->sc_msr & ~(MCR_CTS|MCR_DCD|MCR_RI);
sc->sc_msr |= msr & (MCR_CTS|MCR_DCD|MCR_RI);
ISSET(sc->sc_msr, MCR_CTS) ? "+" : "-",
sc->sc_msr_cts = MCR_CTS;