# USB to Serial Adapter Troubleshooting

- Use a "real" RS-232 serial port, if available, in preference to a USB to Serial Adapter. You'll have no choice but to use a USB to Serial Adapter on modern Apple Macs.
- Verify that the USB to Serial Adapter's device drivers are up-to-date.
- Try a different USB to Serial Adapter.
- Try a different computer. Some combinations of USB to Serial Adapter and USB port are more reliable than others. For example, some laptop computers may not provide sufficent power to USB devices for reliable communications.
- Try changing the K3's RS-232 data rate to 38,400 bits per second using the K3's CONFIG:RS-232 menu. Firmware loading is performed at 38,400 bps, and setting this speed at the start removes the need for the K3 Utility to change the K3's RS-232 speed.
- Some users have found that their combination of computer and USB to Serial Adapter is more reliable at 38,400 than 4800 bps.
- One user reported that his USB to Serial Adapter did not work well when connected through a USB Hub.
- One user of a USB to Serial Adapter found it helpful to add a common ground connection between his laptop computer and K3 chassis.
- A laptop's USB port may be more reliable if the laptop is powered by a power supply rather than its batteries.