The 75-00004 is a 24V (0.62A) power supply replacement for the doorphone models 3226V Vandal-Proof Trunk Port (FXO) Doorphone / 3228V Vandal-Proof Station Port (FXS) Doorphone / 8028 IP Doorphone (Controller + Intercom). This AC mains adapter is rated at 100-240V 47-63Hz (0.4A).