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
7)  caller id (DTMF,ONE RING) to telephone or voip gateway & PABX
    caller id (FSK) to telephone or voip gateway & PABX(Optional)
8)  1 CHL / 4 CHL / 8 CHL/ 16 FWT
9)  1 number calling in, then 8 GSM receiving
10) CLIR(Calling Line Identification Restriction)
11) single-handed power switch
12) LED indicating Hook On/Off,Talking,signal intensity,Power On/Off
13) set dialing delay time
14) talking DTMF Automatic dialing to GSM & to voip gateway & PABX(Optional)
15) SPK & MIC volume regulate
16) provide accumulator charger (Optional)
17) 4SIM automatic rotator (8 CHL 32 SIM cards)(Special Optional)
      - rotator by really clock(4 time oclock)
      - rotator by dial times
      - rotator by total talking minutes
      - rotator by working hours
18) IMEI changing (Special Optional)
19) Simple to install and easy to maintain
20) Steady module & reliable design ensures good performance
21) Strong signals with high gain antenna
22) No noise & Clear voice
23) Suitable for wide voltage range & Low power consumption
24) Suitable for all kinds of weather & environment
25) Offer keypad command sets to difine functions