The ShoreTel BB424 button box is an excellent tool for operators, receptionists, assistants and supervisors. The BB424 provides visibility over other users as well as single-button access to advanced telephony features including transfer, silent monitor and barge in. The BB424 is a USB accessory for the IP485g IP phone and features 24 programmable buttons. Users can also employ the four page buttons across the bottom to program up to 96 buttons total.