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1.It is suitable for automatic instrution amplification telephone system when feed voltage reaches to 33-60v.
6.Double audio dialing.
8.Low frequency group:697,770,852,941Hz.
9.High frequency group:1209,1336,1477Hz.
11.The signal level when the lenght of user's line is 3 km.
12.Standard frequency:Low frequency group:-9db.
13.Hight frenquency group:-7db±3db.
14.Level difference frequency high and low frequency of combined signal:2±1db.
15.The total intermodulation distortion caused by harmonic is 20db lower than wave level.
16.Call transmission index:(5KM)SLR≤12,RLR≤-1,and STML≥10,Input impedance:600Ω.
17.Handsfree operation built-in loud speaker 0.5W.