Thread: ActiveRouting .db file - general discussion

With the introduction of the topo PRO maps by Garmin, also ActiveRouting has been introduced. Spread over various threads, related information can be found but member results are not consistent. Some get it to work on their GPS unit but not in BaseCamp, some get it to work the other way around, and some don't get it to work at all. And if it works in BaseCamp with one map, it may not work the same way with another map. Since the information is scattered over various topo PRO threads, it is not easy to get a grip on the problem. Therefore I started this thread to focus on the issue and have the discussion about the ActiveRouting file in one location.

A few things that puzzle me:

In one of the threads, I noticed the screen shot below, showing the files in the SD:\Garmin\SQL folder of a (genuine) downloaded version of Topo Austria v3:



Note that one zero of the .DB file name is left out at the end in the .UNL file name as well as in the .GMA file name. I assume that's how it is supposed to be. But then, how would that work with the .DB file of for instance Topo Germany 2012 PRO which has the file name 010-D0752-01.db?
Would the .UNL file be named 010-D0752-01.UNL or 010-D0752-0.UNL or 010-D0752-1.UNL???

Some members reported the need for an .UNL file to make it work on their GPS, others say it works without .UNL as well. How can that be explained?

Unfortunately, I don't have a hand-held GPS unit myself (sometimes can borrow from a friend at the other end of the country who I don't see regularly), so I can't try out different setups on the GPS myself. Therefore I welcome any input, feedback, suggestions, comments, experiences, etc on this issue and hope the fog that surrounds the ActiveRouting file eventually clears up.