Name: Pololu Jrk 12v12 TTL Port (COM4) Driver
Author: Pololu

Question 1

Driver install fails or is blocked?

Accepted Answer

Run the Pololu USB Drivers installer as administrator, close the Jrk Configuration Utility and any serial terminal using COM4, then reboot. If Windows blocks the signed driver, check Device Manager for an error and reinstall from Pololu’s package, not Windows Update.

Question 2

Jrk not detected / COM4 missing?

Accepted Answer

Verify the Jrk 12v12 is powered and using a data-capable USB cable; avoid unpowered hubs. In Device Manager, check Ports (COM & LPT) for “Pololu Jrk 12v12 TTL Port.” Unplug/replug, scan for hardware changes, and confirm software opens COM4, not the Jrk Command Port.

Question 3

Version/COM-port conflicts?

Accepted Answer

Uninstall old Pololu drivers and remove stale COM4 entries, then install the latest driver. Close other tools using COM4; if the port changes, update the Jrk software’s serial-port setting.