l Call from VoIP to GSM or GSM to VoIP
l Bulk SMS
l Auto check balance and recharge
l Remote SIM Control
l Outbound call from voip
l Inbound call from gsm
l Remote management
l GSM Channels：32 ports
l Power Adapter: DC12V/4.5A
l CPU: ARM11/700MHz
l RAM: 128M
l Flash: 8M
l GSM Frequency: 850/900/1800/1900MHz
l Max power consumption: 38W
l Net weight: 1.7KG
l Size: 36.2*21*6.5cm
l Operating Tempreture: 0-45℃
l Working Humidity: 10%-90% non condensation
l VoIP Protocols: SIP V2, H.323 V4
l Audio Codecs: g711(alaw/ulaw), g729, g723.1
l DTMF format: SIP INFO, RFC2833, Inband
l Packet Loss Concealment
l Programmable Jitter Buffer: Fixed, Dynamic, Adaptive
l Network Connection: DHCP, PPPOE, Static IP
l STUN Server
l Support English, Chinese
l Support Signaling encryption
l Support media encryption
l Support Media NAT Traversal
l Support Remote control
The concept diagram below shows a simple VoIP network for call center application. It consists of a softswitch/IP PBX and VoIP clients such as an IP phone, a call center operator, and GoIPs. All VoIP clients are configured to register to the softswitch/IP PBX. For the GoIPs, each GSM channel is inserted with a valid SIM card in order to access the GSM network. Both incoming and outgoing calls between the VoIP and GSM/PSTN networks can now be realized. 
