P570Base Users / Max Users 300 / 500 Max Concurrent Calls 60 /120 Max FXS Ports 16 Max FXO/BRI Ports 16 Max GSM/3G/4G Ports 6 Max E1/T1/J1 Ports 2
P560Base Users / Max Users 100 / 200 Max Concurrent Calls 30 / 60 Max FXS Ports 8 Max FXO/BRI Ports 8 Max GSM/3G/4G Ports 4 Max E1/T1/J1 Ports 1
P550Base Users / Max Users 50 Max Concurrent Calls 25 Max FXS Ports 8 Max FXO/BRI Ports 8 Max GSM/3G/4G Ports 4 Max E1/T1/J1 Ports –
P520✓ Base Users / Max Users: 20 ✓ Max Concurrent Calls: 10 ✓ Max FXS Ports: 4 ✓ Max FXO/BRI Ports: 4 ✓ Max GSM/3G/4G Ports: 1 ✓ Max E1/T1/J1 Ports: Not supported