1. Support 8 SIM cards
2. Using SIM card and suitable for GSM850, 900, 1800/1900 MHz (Optional)
3. Making & answering calls after connecting to telephone set
4. Each port can be controlled by reset button
5. Support reverse polarity
6. Available to connect with telephone set, PBX, Billing machine, etc
7. Caller ID
8. Built-in PIN code protection featured with locking device/card/network
9. Supports the functions of redialing and hands-free
10. Voice adjustment of calling in and out
11. Featured with indicator of signal intensity, working status, breakdown, etc
12. Setting up and modification of parameters through the phone set