YRM 20N Receiver module is inserted inside the back panel of the lock to pair it with Remote control and Video Door Phone (VDP).Earlier generation of the lock uses YRM 20 Receiver Module
It works with : YDM 3109 - YMF 40 - YDD 424 - YRD 41 - J 20 - YDR 4110 - YDM 7116 - YDR 50G - YMI 70 - YDM 4109 - G Slide