EnGenius SN920ULTRA 900 MHz DSS Expandable Cordless Phone 900 MHz digital spread spectrum signal, 900-milliwatt transmission power Works as cordless phone and digital full-duplex 2-way radio Expandable system, network up to 4 base units and 36 handsets (sold separately) Call transfer plus call manager--program handset to receive all calls or just transferred calls Digital security with frequency hopping