Features: 1) Equipped with independent wireless module to make more steady and reliable 2) Supports to send line reversal signal 3) Supports to send caller ID signal 4) Supports LED indicating work status as network, wireless module and the line 5) Supports to lock SIM/UIM card 6) Supports to dial prefix code with the number 7) Supports to limit to the make IDD, DDD, or local call 8) Compatibility to Billing Meter 9) Connects to the standard telephone 10) Operation with wide voltage and low power consumption 11) With external antenna, supports multi-type AC power specification