Features: 1) Makes DDD, IDD and local calls and charges fee with valid cards, such as IC cards and magnetic cards 2) Makes free calls without cards 3) Not permitted to dial the forbidden phone numbers preset via management system 4) Two billing methods: polar reverse signal and 16kHz or 12kHz metering pulses 5) Dynamic displays the balance of the card and call duration 6) Support advertisement playing 7) Over-voltage and over-current protection 8) Working under the supervisor of management system 9) Downloads tariff rate table and parameters to the phones via management system