Call Paramedic unit or Fire unit


I developp an emergency menu for a server and I want to add a feature that allow players (by pressing a button in my menu) to call a Paramedic or Fire unit like in the original game (when you call 911 with the mobile phone). I know exactly how to make the menu and so on but I don’t know what is the native or the code that dispatch emergency to player. Can you help me ?