CIAB_PRA_CTS
#define SETCTS(c) (c &= ~CIAB_PRA_CTS)
#define CLRCTS(c) (c |= CIAB_PRA_CTS)
#define ISCTS(c) (!(c & CIAB_PRA_CTS))
ub |= CIAB_PRA_CTS;
if (ub & CIAB_PRA_CTS)
if ((istat & CIAB_PRA_CTS) && (tp->t_state & TS_ISOPEN) &&