1. 8 channels GSM <-> VoIP connection ,8 SIM cards
2. USSD for balance checking
3. Support hot plug for SIM card
4. Support RC4, VOS encryption5. GSM network 850/900M/1800M/1900M 
6. Support IMEI changeable
7. Support white list and black list8. Support SMS send and receive, SMS group
send
9. Exact caller ID detect and display10. Extra second dialing, for card sending and
call back11. Hi-end voice DSP processor(AudioCodec),echo cancellation
12. Flexible dialing rule, can use at anywhere
13. Dual server mode, insure the device working safely
14. LCR feature, calling route
15. Smart call back feature16. Based on SIP2.0(RFC3261) protocol17.Voice codec:
G.729，G.723，G.711 A/U,etc.