As a youngster on D-star im learing new things every day.
Just by listening to other hams i now know how Call-sign routing works.

You having a QSO with a Ham on a reflector lets say DCS007U.
The next day you like to work this Ham again and like to call him direct via de call-sign routing.

The memmory in your Transciever and on the database of the repeaters knows where you last been heard.
In this way it may or may not work the call-sign routing.

How does it work on my IC-E92D

You are having a qso on a repeater link with the ham you are talking to.
For instance it is DCS007U.
The next day you like to call him again direct.

Just do the following steps.

Push CALL when holding the button you can rotate to the call you like to speak to.
Release the call button. The IC-E92D with send a double beep.
Now Push the talk button and what repeater you are the call-sign routing will try to call the person on the last known repeater reflector they have been.

If the station on the otherside changed the next day from reflector the call-sign routing will try to connect to the correct repeater and reflector, if the repeater support the call-sign routing.
Otherwise you will stay on the repeater and nothing will happen.

Dvap Dongle doesn’t support call-sign routing. It will only work on repeaters.

 

just another 2 cent of my knowledge