set_control_line
retval = set_control_line(board, IB_BUS_REN, 0);
int retval = set_control_line(board, IB_BUS_ATN, 0);
retval = set_control_line(board, IB_BUS_EOI, 1);
retval = set_control_line(board, IB_BUS_EOI, 0);
retval = set_control_line(board, IB_BUS_REN, enable ? 1 : 0);
retval = set_control_line(board, IB_BUS_ATN, 1);
return set_control_line(hw, priority, channel_idx, COMCTRL_DTR, state);
return set_control_line(hw, priority, channel_idx, COMCTRL_RTS, state);