Yes, I have personal ring group with the pilot number 412 as following:
412 - my desk phone 5312
512 - EHDU used for calling to my mobile
312 - UCA, App Server Port
412 is not a Hotdesk user, it is permanent on the 5312 phone, however I have another phone (5212) where I have 412 as a Multicall key.
Actually "HCI/CTI/TAPI Call Control Allowed" and "HCI/CTI/TAPI Monitor Allowed" are by default set to Yes, I checked all the COS' that are available and all have these to options set to Yes. So all devices, trunks have these 2 options enabled.
Version is MCD 5.0 SP2 PR2 running on CXi.