Call control protocol: SIP(RFC-3261) or H.323 V4 or MGCP. Echo cancellation: G.165/G.167 16ms. IP Address: PPPoE, DHCP client, Static IP. LCD Display: Dialed Number, Coin Value, Remaining Credit, Reminding Message, Self-Diagnostic Message, and Revenue Information. Function Keys: Voice Amplification, Language Choice, Redial, Follow-on-Call. Optional Web-based management system for tariff / rate ...