I have use a Openstage 40 (V3.R5.20). Heres a little list of all the Things that i tested and the Results :
- Receiving Calls

- Making Calls

- Putting Calls on Hold

- Ending Calls

- Call Completion

- Declining Calls (Yes and No. When the Phone rings and you Press Decline in the WebClient the Call continues.If you press Decline on the other end (in this Case a Dect phone) reads out "Transfer failed" and then the Calls ends.)
- Using the DND Feature of the Openstage to turn on DND in 3CX

- Mailbox Notifications (MWI)

- HD-Calls

- Taking Calls on a Different Device with the Same User

(It shows the Call as Missed in the Call Log of the Phone)
- Configuring BLF Keys using 3CX

- 3CX Phonebook

(Since the 3CX Phonebook dosnt use LDAP it wont work on any OpenStage)
- Details of the Phone in the Phones List of 3CX

(They kind of Work but in the Place where the Manufactuer is Listed it shows OpenStage instead of Siemens or Unify and at the Model it shows the Software Version instead of the Openstage 40. Also the Firmware-Version reads out "simple-usCSTA"
-Call forwarding

- Provisioning
