|  | Z-TWS4-RT | Z-TWS4-RT | R-PASS-S | SSD-S | 
| Fast Ethernet ports | 2 | 2 | 4 | 2 | 
| Serial Ports | 3 | 3 | 3 | 2 | 
| USB ports | 1 | 1 | 2 | 2 | 
| Integrated I/O | 6DI/DO, 2AI (mA,V) | 6DI/DO, 2AI (mA,V) | 4DI, 4DO, 2AI (mA,V) | 2DI/DO | 
| Environment Configuration | Z-NET4 | Z-NET4 | Z-NET4 | Z-NET4 | 
| PLC Programming | IEC 61131-1, Straton | IEC 61131-1, Straton | IEC 61131-1, Straton | IEC 61131-1, Straton | 
| Remote control libraries | Yes | Yes | Yes | Yes | 
| Max. no. of variables / TAGs | 1000 | 1000 | 1000 | 1000 | 
| Program size | 2048 kB | 2048 kB | 2048 kB | 2048 kB | 
| Diagnostics | Web Server | Web Server | Web Server | Web Server | 
| Data Recording and Display | Data Recorder Trend Viewer
 Web Factory
 | Data Recorder Trend Viewer
 Web Factory
 | Data Recorder Trend Viewer
 Web Factory
 | Data Recorder Trend Viewer
 Web Factory
 | 
| IT protocols | FTP / SFTP server HTTP / HTTPS server
 SMTP / SMTPS client
 SNMP
 SAMBA
 | FTP / SFTP server HTTP / HTTPS server
 SMTP / SMTPS client
 SNMP
 SAMBA
 | FTP / SFTP server HTTP / HTTPS server
 SMTP / SMTPS client
 SNMP
 SAMBA
 | FTP / SFTP server HTTP / HTTPS server
 SMTP / SMTPS client
 SNMP
 SAMBA
 | 
| Fieldbus | ModBUS RTU ModBUS TCP-IP
 S7comm
 M-BUS (with Z-MBUS accessory)
 | ModBUS RTU ModBUS TCP-IP
 S7comm
 M-BUS (with Z-MBUS accessory)
 | ModBUS RTU ModBUS TCP-IP
 S7comm
 M-BUS (with Z-MBUS accessory)
 | ModBUS RTU ModBUS TCP-IP
 S7comm
 M-BUS (with Z-MBUS accessory)
 | 
| IoT protocols | OPC UA OPC DA
 MQTT
 | OPC UA OPC DA
 MQTT
 | OPC UA OPC DA
 MQTT
 | OPC UA OPC DA
 MQTT
 | 
| Energy Protocols | IEC 60870-101 Slave IEC 60870-104 Master / Slave
 IEC 61850 Client / Server
 | IEC 60870-101 Slave IEC 60870-104 Master / Slave
 IEC 61850 Client / Server
 | IEC 60870-101 Slave IEC 60870-104 Master / Slave
 IEC 61850 Client / Server
 | IEC 60870-101 Slave IEC 60870-104 Master / Slave
 IEC 61850 Client / Server
 | 
| Security | TLS 1.2/1.3, penetration test, x.509 certificates | TLS 1.2/1.3, penetration test, x.509 certificates | TLS 1.2/1.3, penetration test, x.509 certificates | TLS 1.2/1.3, penetration test, x.509 certificates | 
| HMI | virtual via HTML | virtual via HTML | virtual via HTML | physical 7“ and virtual via HTML | 
| Cloud Support | x | x | x | x | 
| VPN support | x | x | x | x | 
| Energy Controller | x | x | x | x | 
| Datalogger | x | x | x | x | 
| Gateway | x | x | x | x | 
| Alarm management | x | x | x | x | 
| Voice alarms | x | x | x | x | 
| Custom script | x | x | x | x | 
| LAN router | x | x | x | x | 
| LAN Ports | 2 (LAN/WAN) | 2 (LAN/WAN) | 4 (3LAN/WAN) | 2 (LAN/WAN) | 
| 4G/LTE Router | - | x | x (with R-COMM accessory) | - | 
| LAN / 4G redundant connectivity | - | x | - | - | 
| Remote assistance unit | x (with external line/modem) | x | x (with external line/modem, R-COMM accessory) | x (with external line/modem) | 
| Remote control unit | x (with external line/modem) | x | x (with external line/modem, R-COMM accessory) | x (with external line/modem) | 
| WiFi | - | - | x (verify model) Wi-Fi 802.11 b/g/n, band 2.4 ÷ 2.4835 GHz
 | Wi-Fi 802.11 b/g/n, banda 2.4 ÷ 2,4835 GHz |