1. High impedance sound record,get sound from telephone line.2. RJ11 phone connector shape, simply connect to telephone RJ11 port throught phone cable,no need attention the in,out port driection,the recorder will auto recognize.3. Less charging, plug to use, built in special circuit gets power from phone system, but first time use need charge it, when connected to the telphone line, you may need take out charge it by USB charger every week if your phone call is busy,for normal use, you may need take it out to charge by USB charger every month.4.Plug to use: plug the telephone line to the RJ11 port and turn power switch to on to start recording.You can place it in office,hotel,home with simple connection,then it will auto start recording when phone call made.5.Cycle recording: support cycle of recording, when the memory reached fully, it will overwritten the oldest recorded files, works by first in first out mode.Memory: 32GB -SD cardRecording Time: 7 - 30days after full Recording Formats: WAVDate and Time Stamp: YesBattery: 700mah lithium battery: /Win 7/8/ OS / OSRecording Bitrate: 192KbpsUSB Port: USB 2.0Frequency Response: 20Hz -20KHzWorking Temperature: 0 - 40Dimension: 59mm x 36mm x 25mmColour:WhiteMaterial:plasticPackage Contents:1 x RJ11 Telephone Recorder1 x Telephone Line1 x USB CableOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.