General Features:

• SIM card slot for GSM connectivity
• Supports VoIP protocols (SIP, H.323, etc.)
• Compatible with various GSM frequencies (2G, 3G, 4G/LTE)
• Can handle multiple GSM channels (e.g., 1 to 16 channels)
• Provides connectivity for VoIP calls via GSM network
• Web-based management interface
• Support for call forwarding, call routing, and SMS functions

GSM Specifications:

• GSM frequency bands: Quad-band (850/900/1800/1900 MHz) or Tri-band (900/1800/1900 MHz)
• 2G/3G/4G/LTE support (depending on model)
• SIM card support: Standard, micro, or nano SIM (depending on model)
• GSM module: Integrated or replaceable

VoIP Features:

• Supports multiple VoIP accounts or SIP trunks
• SIP compliance: SIP v2 (RFC3261)
• VoIP codecs: G.711 (A/μ), G.729, G.722, G.723, G.726, Opus
• Support for call detail records (CDR)
• Echo cancellation and noise reduction
• Call control features: Call transfer, call hold, call waiting, call forwarding
• SMS support: Send/receive SMS via web interface

Connectivity:

• Ethernet ports: 1 to 4 ports (10/100/1000 Mbps) for network connection
• Serial port: For console management (optional)
• USB ports: For additional peripherals or firmware updates (optional)
• Power over Ethernet (PoE): Optional, depending on model
• Power supply: AC adapter (input: 100-240V, output: 12V/1A or 5V/2A, depending on model)

Management and Configuration:

• Web-based graphical user interface (GUI) for configuration and monitoring
• Remote management support (e.g., via SSH, Telnet, or SNMP)
• Auto-provisioning support for SIP settings
• Firmware upgrade via web interface or USB

Security:

• Support for SRTP/TLS for secure VoIP communications
• HTTPS for secure web access
• Built-in firewall and NAT traversal support
• VPN support: IPsec, PPTP, L2TP (depending on model)

Performance:

• Call capacity: Up to 32 simultaneous calls (depending on model and GSM channels)
• Call setup time: Typically less than 2 seconds
• Network throughput: Depends on GSM and VoIP configurations

Physical and Environmental:

• Dimensions: Varies by model (typically compact, rack-mountable or desktop)
• Operating temperature: 0-40°C (32-104°F)
• Operating humidity: 10-90% (non-condensing)
• Weight: Varies by model (typically lightweight)