IP PBXs S20 20 Users 10 Concurrent Calls Max FXS Ports : 4 Max FXO/BRI Ports : 4 Max Cellular Ports : 1 20 VoIP Trunks Order Now S50 50 Users 25 Concurrent Calls Max FXS Ports : 8 Max FXO Ports : 8 Max Cellular Ports : 4 50 VoIP Trunks Order Now S100 Up to 200 Users Up to 60 Concurrent Calls Max FXS Ports : 16 Max FXO Ports : 16 Max Cellular Ports : 4 Max E1/T1/J1 Ports : 2 100 VoIP Trunks Order Now Modules FXS Module For analog devices Order Now FXO Module For landlines Order Now GSM Module For SIM Cards Order Now Gateways FXO Gateway Connects analog telephone lines or PABX extension interface to VoIP networksA cost-effective and reliable solution for office-to-office voice connectivity Order Now FXS Gateway Cutting-edge products that connect legacy telephones, fax machines and PBX systems with IP telephony networks and IP-based PBX systems. Order Now PRI Gateway Bridge the gap between ISDN telephony connections such as common RJ-48c / T1 interfacesto provide dial tone to most VoIP PBX phone systems Order Now