TXBUF_AVAIL      1773 src/simh/sim_tmxr.c if ((lp->txbfd && !lp->notelnet) || (TXBUF_AVAIL(lp) > 1)) {/* room for char (+ IAC)? */
TXBUF_AVAIL      1777 src/simh/sim_tmxr.c     if ((!lp->txbfd) && ((unsigned long int)TXBUF_AVAIL (lp) <= TMXR_GUARD)) /* near full? */