Mitel SX-200 Hotline Phone

On a Mitel SX-200 system, it's a little obscure but still possible to take an analog extension and have it automatically call a predefined number when it goes off hook. This is useful for a lobby or door phone, and especially useful for a security door phone that doesn't have buttons on it. To do this you just need to create a new COS (form 3) for the phone(s), enable option 228 (Manual Line), and assign that COS to the phone. Once the phone goes off hook, it will immediately ring the operator. To enable option 228 you will probably have to show disabled options and enable it.