CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING
sc->sc_flags |= CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING;
sc->sc_flags &= ~CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING;
} else if (sc->sc_flags & CDCEEM_SC_FLAGS_ECHO_RESPONSE_PENDING) {