code: int getInterFrameDelay() {
          if (commPort.getBaudRate() > 19200) {
              return 1750;
          }
          else {
              return Math.max(getCharInterval(Modbus.INTER_MESSAGE_GAP), Modbus.MINIMUM_TRANSMIT_DELAY);
          }
      }
docs: In microseconds
  
  @return Delay between frames