Is it possible to conduct a public meeting where all board members are in attendance via electronic device (e.g. computer, phone etc.)?
It is definitely possible. The crucial elements to insure you are conducting a legal public meeting are: (1) post the meeting date and time, as well as any details necessary for the public to be able to "attend" the meeting; (2) make sure whatever arrangements you are making include an opportunity for the public to "attend" the meeting where the board is conducting its business. This includes making sure the location is accessible if you are providing a public viewing spot; (3) have a process for public participation when it is appropriate and provided for in the agenda; and (4) insure minutes are taken of the meeting so that all of the business of the board is still recorded. I would recommend the use of roll call votes in this situation in order to insure an accurate reflection of board members' votes.
There are several options on how you can structure this type of meeting. For instance, you can have a room set up with a computer and a screen for the public to view and participate when appropriate. The use of meeting software such as Go to Meeting is also a possibility. In this situation, it would be necessary for the public to be given instructions for logging into the meeting and participating. It would also be important for there to be no expense to the public for participation, including phone charges.