Hi there. I am from Romania too, I have same problem with Electra Intercoms. I have wrote the original Electra key on a blank rewritable EM4100. But it seams to be a problem with the key that are not originally from Electra.
I have checked the token. I have the same token on both keys but the copied key is not read by the reader. I mean there is no feedback from reader, no buzzing, no lighting nothing.
I was thinking to make a copy at special key copy center or to ask them for buying a blank key from them.
@philiplykov you can check in any Mall Shopping Center and also in Dedeman for a key copy stand.