My customer has UCM 7.1 with Unity Connection 7.x. They have Mitel SIP based phones (model 5330 & 5320) which they want to use with UCM. I'm not sure how this will work. I think I need to add 3rd Party SIP Phone (Basic) in UCM but not sure what else is involved (like maunal configuration on Mitel phones etc.). Please let me know if anyone has any experience in this, I really appreciate the help.