Hello Monique, LocoNet is a connectivity system which allows devices to communicate to each other, based on a simple and cheap cabling system.
6021-LocoNet-Adapter is a device that allows the connection of LocoNet devices to a 6021.
You can connect any LocoNet compliant device to this Adapter ( at least, all devices produced by Uhlenbrock, such as IRIS - an infrared remote control for 80 locos and 256 turnouts, Daisy Control - a wired remote control for 80 locos and 256 turnouts, Profi Control - a mimic control of real locos, IB_Control - an IB panel without main system, etc, etc. and it's forseen for September, 2004.
You won't have all the possibilities of an IB, but you'll be able to connect nearly every device which can be connected to an IB, with only a fraction of its cost.
While Märklin is promising a system that will be nearly incompatible with your 6021, Uhlenbrock offers an upgrade of it.
They say: "Werten Sie Ihre 6021 auf!", what means: add value to your 6021...
Unfortunately, there is no english version of the leaflet, so far.
Hope this can be of help.
Regards,

Hello Monique, the Lokmaus is not included in the list of devices announced by Uhlenbrock as connectable to the 6021 thru the adapter. The Adapter with an IRIS (Infrared Control, 80 locos, 256 turnouts) sells for 109 Eur.
Regards,

There is an English version of the leaflet on RJFtrains, at:

http://www.rjftrains.com/intellibox/Neu2004e1.pdf

Funck

Hello Monique, a Maus-Adapter 68340 (68Eur + LokMaus) is needed for connecting LokMaus to LocoNet and thru it to the IB, nothing is said by Uhlenbrock about connecting it to 6021-adapter.
Daisy handcontrol sells for 118Eur. Perhaps this is a cheaper option than LokMaus+68340, and we don´t know if LM+68340 works with a 6021.
Regards,

Many thanks to everybody for the clear explanations. I think I will get the adapter and a Daisy (when available) as Jorge suggests, and consign the Lokmaus as a gift to someone with a DC train...
Monique