Hi guys, here are the 3rd Party Extention's all features that supported by Samsung PBX
 Hold/Resume
 Music on Hold
 Consultation Call
 Transfer (Consultation/Blind)
 Call Waiting
 Call Pickup
 Call Forward (All/Busy/No-Answer)
 Conference
 Call Park (System Hold)
 DND
 Call Back
 Voice Mail Indication
please check the link. You can find everyting about SIP Extentions.
https://hotfile.com/dl/131030094/c99f6eb/SIP_Station_Manual_For_OfficeServ_v112.doc.html