Product Name: 4 channels GSM FWT with auto IMEI changer
Price: US$
Detail: function :
1) GSM 850MHz 900MHz 1800MHz 1900MHz
CDMA 800MHz(Optional)
2) standard RJ-11 to telephone or voip gateway & PABX
3) 450Hz Dial-tone and Busy-tone
4) 50V in idle and 75V in ringing and 9-12V in talking
5) DTMF detector in RJ-11
6) precise reverse polarity <