Comtel One Digital Bedienungsanleitung Seite 35

2. Operation from batteries
Press and slide open the battery door in direction as shown.
Insert three pieces AAA size (UM-4) alkaline batteries into the
compartment.
Observe correct polarities indication.
N.B. For best performance, do not mix use old and new batteries or
alkaline and rechargeable batteries.
(B) Parent unit equipped with rechargeable battery and rapid
Charger
1. Operation from Ni-Mh rechargeable battery pack
Press and slide open the battery door in direction as shown.
Insert the supplied Ni-Mh rechargeable battery pack into the compartment.
Make sure the two terminals on battery pack are in contact with the metal
springs located inside the compartment.