1) 8 port(8 SIM Card) wireless (GSM or CDMA) VOIP gateway. 2)support self billing,account balance display 3)OEM ... of Channels4GSM8GSMFrequency850/900/1800/1900MHzCall Control ProtocolsSIPVoice CodecsG.729A, G.723.1, G.711 a/ulawNetwork ProtocolsIPv4, TCP, UDP, PPPoE, DHCP, DNS ... need support CDMA/WCDMA ,you need order SinoV-X500 type. 4 Port Wireless GSM Voip Gateway