IF-DA are not compatible with LEF-3. In theory.

In practice – it is possible to connect 1 (only) IF-DA and 1 LEF-3 (or LEF-5). 1 IF-DA with 1 LEF-3 was working just nice.
We have tested together 2 IF-DA with 1 LEF-3 and the system was not working. One of the IF-DA in such arrangement was contantly calling LEF-3. Below is the wiring diagram for 1 IF-DA and 1 LEF-3.