Instruct: Classify Amazon reviews into positive or negative sentiment
Query: buyer beware - extension phones?

Be warned that this, and some other expandable phone systems, do not allow an additional handset to easily join an existing conversation. The handset currently using the line must first put the outside party on hold, figure out which of the expansion handsets wants to join the conversation, ring that specific handset, and then remove the hold condition. Not exactly convenient.On the plus side, sound quality and range are good, and as advertised, the phones generate no interference to degrade wi-fi networks.