This quickstart video will show you how to pair a Bluetooth connection with the HV Diagnostics VLF Unit HVA28TD. You can see a more detailed video here:    • HV Diagnostics HVA28TD Communications...  

What about the other VLF units? As you get higher up, HV Diagnostics has done a good job of marrying up the unit with the HVD software, and therefore pairing should not be necessary. That includes units HVA30, HVA34, HVA45TD, HVA60, HVA90 and HVA120.

Need to rent the HVA28TD or need to request the manual? Visit: https://protecequip.com/products/hv-d...

From HV Diagnostics: In most cases the pin is not needed at all for connecting software to device since the user should be choosing the auto setting in the drop down menu for com port connections etc. This never requires the “welcome” pin. There may be cases where they may want to connect manually if auto doesn’t work for some reason with their pc/laptop. That situation is extremely rare, though. Adding a sticker or label with the “welcome” pin may confuse the process.