Lagendorf used to be a very important and inovative company which specialized in watch movements. Sadly Lagendorf has not survived quartz crisis even though it was bought by SSIH group in 1970.
Lagendorf showed it's inovative approach also in the development of it's alarm movement Lagendorf 1241 (and upgrades 1243 and 1244). Lagendorf 1241 is quite different than any other alarm movement developed until then. It has two spring barrels but only one stem and crown with which everything is operated. Instructions for this movements are more complicated and watch is not "user friendly" - the reason is again that everything is operated with just one crown.
Lagendorf used brand Lanco for their watches, alarm watches were named Lanco-fon. Other companies also used this movement in their watches but almost all of them used suffix -fon in their name of the watches (i.e. Larex-fon, etc.).
I have only watch with 1241 movement version in my collection.
Crown in position 0: winding time (turning crown backwards) or alarm (turning crown forward). When alarm is fully winded, with turning crown forward again alarm is activated (dot above 12 turns red). Turning crown backward deactivates alarm (dot above 12 turns white).
Crown in position 1: Setting the alarm crown. Only turning crown forward is allowed.
Crown in position 2: Setting the time. Only turning crown backward is allowed.