Probably a stretch question for the General Forum, but hoping not to have to enter into each individual group!

I work for a Telecom Provider. Looking for general opinions on which of the PBX manufactures support ISDN Redirecting Number, used with call forwarding..... or said differently, which ones do NOT support this option. If you could provide specifics details on PBX make/model support requirements (s/w version, feature bundle,etc.), I would certainly welcome any and all information. Thx!