ST-NCTL210 Network Serial Port Expander
- Black
- DC-powered
- AC-powered
- Tabletop
- Wall
- Fast
- Ethernet (IEEE 802.3)
- Non-stackable
- RJ-45
Specifications
ST-NCTL210 Network Serial Port Expander is a professional RS-232, RS-422 and RS-485 serial device server designed for reliable serial-to-Ethernet communication in commercial AV and automation systems. The ST-NCTL210 Network Serial Port Expander features four serial ports, four relay outputs, TCP/IP and UDP communication, built-in web server, API control, and 100M Ethernet connectivity for seamless integration with AMX, Crestron, RTI and third-party control systems. Designed for conference rooms, classrooms, industrial automation, control rooms, and commercial AV installations, the ST-NCTL210 Network Serial Port Expander delivers stable communication, flexible protocol conversion, and dependable network-based serial control. The ST-NCTL210 Network Serial Port Expander provides professional performance, simple configuration, and reliable operation for demanding control applications.
ST-NCTL210 Network Serial Port Expander is a professional RS-232, RS-422 and RS-485 serial communication solution designed for reliable serial-to-Ethernet integration in commercial AV, automation, and control systems. The ST-NCTL210 Network Serial Port Expander features four extended serial ports, four relay outputs, TCP/IP and UDP communication, a built-in web server, API command control, and 10/100M Ethernet connectivity for seamless integration with AMX, Crestron, RTI, and third-party control platforms. Designed for conference rooms, classrooms, industrial automation, command centers, smart buildings, and commercial AV installations, the ST-NCTL210 Network Serial Port Expander delivers stable communication, flexible protocol conversion, and dependable network-based device control. The ST-NCTL210 Network Serial Port Expander provides professional performance, simple configuration, and reliable operation for demanding automation and serial control applications.
Features
☆ 4 extended serial ports — COM1 & COM2 support RS-232 / RS-232+HW Flow / RS-422 / RS-485; COM3 & COM4 support RS-232 / RS-232+HW Flow
☆ Universal baud rates: 2400, 4800, 9600, 14400, 19200, 38400, 56000, 57600, 115200
☆ Full frame buffering — large TX/RX buffer per port; data queue support; up to 512 bytes per frame
☆ TCP & UDP transparent — COM1–4 TCP ports 8001–8004; UDP local ports 9001–9004; system port 8005 / 9005
☆ 4 independent relay ports — normally-open contacts, isolated, rated up to 1A / 24V DC/AC
☆ Built-in web server — configure from any browser on PC, tablet or mobile; no software required
☆ 100M Ethernet + RS-232 — compatible with AMX, Crestron, RTI and all third-party control systems
☆ API command control — full ASCII command set over serial or TCP/UDP for system integration
☆ Device name support — rename/remark the device name (max 8 characters)
Package Contents
① 1x Network Serial Port Expander
② 2x 5pin-3.81mm Phoenix Connector (male)
③ 2x 7pin-3.81mm Phoenix Connector (male)
④ 1x 8pin-3.81mm Phoenix Connector (male)
⑤ 2x 9pin-3.81mm Phoenix Connector (male)
⑥ 4x Machine Screw
⑦ 2x Mounting Ear
⑧ 1x 24V/1A Power Adaptor + 2pin-3.5mm Phoenix Connector
⑨ 1x User Manual
Specifications
| Technical | |
| RS-232 | Full duplex; configurable hardware flow control |
| RS-422 | Full duplex communication mode |
| RS-485 | Half duplex communication mode |
| Baud Rate | 2400 / 4800 / 9600 / 14400 / 19200 / 38400 / 56000 / 57600 / 115200 |
| LAN | 10/100M Ethernet interface (RJ45) |
| Relay Output | 4x normally-open, isolated — up to 1A / 24V DC/AC |
| Connection | |
| Input | 1x LAN [RJ45] 1x MAIN COM [7pin-3.81mm phoenix connector] 1x DC 24V [2pin phoenix connector] |
| Output | 1x NEXT COM [7pin-3.81mm phoenix connector, cascade output] 1x COM 1 [9pin-3.81mm phoenix connector, RS-232/422/485] 1x COM 2 [9pin-3.81mm phoenix connector, RS-232/422/485] 1x COM 3 [5pin-3.81mm phoenix connector, RS-232] 1x COM 4 [5pin-3.81mm phoenix connector, RS-232] 1x RELAY OUTPUT [8pin-3.81mm phoenix connector] |
| Mechanical | |
| Housing | Metal Enclosure — Black |
| Dimensions | 147mm [W] × 130mm [D] × 42mm [H] |
| Weight | 673g |
| Power Supply | Input: AC100–240V 50/60Hz; Output: DC 24V / 1A |
| Power Consumption (Max) | <2W |
| Operating Temperature | 0°C ~ 40°C / 32°F ~ 104°F |
| Storage Temperature | -20°C ~ 60°C / -4°F ~ 140°F |
| Operating Humidity | 20%~90% (relative humidity, non-condensing) |
Operation Controls and Functions
Front Panel

| No. | Name | Function Description |
|---|---|---|
| 1 | LAN LED (Green) | Network connection indicator — flashes when network communication is active. |
| 2 | POWER LED (Green) | On when the device is powered up. |
| 3 | RELAY LEDs (Green × 4) | Relay status indicator for each of the 4 relay channels — stays on when the corresponding relay is set to closed. |
| 4 | TX/RX LEDs (MAIN, COM1–COM4) | Data activity indicators for each serial port — red flashes on transmit (TX), yellow flashes on receive (RX). |
Rear Panel
| No. | Name | Function Description |
|---|---|---|
| 5 | DC 24V Port | DC 24V / 1A power input via 2pin phoenix connector. |
| 6 | RESET Button | Hold for 5 seconds to restore factory default settings. IP address restores to 192.168.1.100. |
| 7 | LAN Port | 10/100M network port (RJ45). Use a direct (straight-through) UTP cable — do not use a crossover cable. |
| 8 | MAIN COM Port | Main serial port for connection to a central control system or PC. 7pin phoenix connector. RS-232: PIN5=GND, PIN6=TXD, PIN7=RXD RS-422: PIN1=RX−, PIN2=RX+, PIN3=TX−, PIN4=TX+, PIN5=GND RS-485: Short PIN1(RX−)+PIN3(TX−) → B; PIN2(RX+)+PIN4(TX+) → A |
| 9 | NEXT COM Port | Main serial port cascade output — same pin-out as MAIN COM. Used to daisy-chain additional units. |
| 10 | RELAY OUTPUT Port | 4x independent, isolated, normally-open relay contacts via 8pin phoenix connector. Maximum rating: 1A / 24V DC/AC. |
| 11 | COM1 & COM2 Ports | Extended serial ports 1 and 2. 9pin phoenix connector. Support RS-232+HW Flow / RS-422 / RS-485. PIN1=RX−, PIN2=RX+, PIN3=TX−, PIN4=TX+, PIN5=GND, PIN8=RTS, PIN9=CTS |
| 12 | COM3 & COM4 Ports | Extended serial ports 3 and 4. 5pin phoenix connector. Support RS-232+HW Flow only. PIN5=GND, PIN6=TXD, PIN7=RXD, PIN8=RTS, PIN9=CTS |
Default Network & Port Settings
| IP Address | 192.168.1.100 |
| Subnet Mask | 255.255.255.0 |
| Gateway | 192.168.1.1 |
| IP Mode | DHCP OFF (static) |
| TCP/UDP Mode | TCP |
| COM1–4 TCP Ports | 8001 / 8002 / 8003 / 8004 |
| System TCP Port | 8005 |
| COM1–4 UDP Local Ports | 9001 / 9002 / 9003 / 9004 |
| System UDP Local Port | 9005 |
| COM1–4 UDP Remote Ports | 1001 / 1002 / 1003 / 1004 |
| System UDP Remote Port | 1005 |
| Main COM Baud Rate | 115200 (8 data bits, 1 stop bit, no parity) |
Application Example

Note: Use straight-through (T568A or T568B) UTP cable for the LAN connection — do not use a crossover cable. Use of a surge protection device is strongly recommended.
ST-NCTL210 Network Serial Port Expander is a professional RS-232, RS-422 and RS-485 serial device server designed for reliable serial-to-Ethernet communication in commercial AV and automation systems. The ST-NCTL210 Network Serial Port Expander features four serial ports, four relay outputs, TCP/IP and UDP communication, built-in web server, API control, and 100M Ethernet connectivity for seamless integration with AMX, Crestron, RTI and third-party control systems. Designed for conference rooms, classrooms, industrial automation, control rooms, and commercial AV installations, the ST-NCTL210 Network Serial Port Expander delivers stable communication, flexible protocol conversion, and dependable network-based serial control. The ST-NCTL210 Network Serial Port Expander provides professional performance, simple configuration, and reliable operation for demanding control applications.
ST-NCTL210 Network Serial Port Expander is a professional RS-232, RS-422 and RS-485 serial communication solution designed for reliable serial-to-Ethernet integration in commercial AV, automation, and control systems. The ST-NCTL210 Network Serial Port Expander features four extended serial ports, four relay outputs, TCP/IP and UDP communication, a built-in web server, API command control, and 10/100M Ethernet connectivity for seamless integration with AMX, Crestron, RTI, and third-party control platforms. Designed for conference rooms, classrooms, industrial automation, command centers, smart buildings, and commercial AV installations, the ST-NCTL210 Network Serial Port Expander delivers stable communication, flexible protocol conversion, and dependable network-based device control. The ST-NCTL210 Network Serial Port Expander provides professional performance, simple configuration, and reliable operation for demanding automation and serial control applications.
Features
☆ 4 extended serial ports — COM1 & COM2 support RS-232 / RS-232+HW Flow / RS-422 / RS-485; COM3 & COM4 support RS-232 / RS-232+HW Flow
☆ Universal baud rates: 2400, 4800, 9600, 14400, 19200, 38400, 56000, 57600, 115200
☆ Full frame buffering — large TX/RX buffer per port; data queue support; up to 512 bytes per frame
☆ TCP & UDP transparent — COM1–4 TCP ports 8001–8004; UDP local ports 9001–9004; system port 8005 / 9005
☆ 4 independent relay ports — normally-open contacts, isolated, rated up to 1A / 24V DC/AC
☆ Built-in web server — configure from any browser on PC, tablet or mobile; no software required
☆ 100M Ethernet + RS-232 — compatible with AMX, Crestron, RTI and all third-party control systems
☆ API command control — full ASCII command set over serial or TCP/UDP for system integration
☆ Device name support — rename/remark the device name (max 8 characters)
Package Contents
① 1x Network Serial Port Expander
② 2x 5pin-3.81mm Phoenix Connector (male)
③ 2x 7pin-3.81mm Phoenix Connector (male)
④ 1x 8pin-3.81mm Phoenix Connector (male)
⑤ 2x 9pin-3.81mm Phoenix Connector (male)
⑥ 4x Machine Screw
⑦ 2x Mounting Ear
⑧ 1x 24V/1A Power Adaptor + 2pin-3.5mm Phoenix Connector
⑨ 1x User Manual
Specifications
| Technical | |
| RS-232 | Full duplex; configurable hardware flow control |
| RS-422 | Full duplex communication mode |
| RS-485 | Half duplex communication mode |
| Baud Rate | 2400 / 4800 / 9600 / 14400 / 19200 / 38400 / 56000 / 57600 / 115200 |
| LAN | 10/100M Ethernet interface (RJ45) |
| Relay Output | 4x normally-open, isolated — up to 1A / 24V DC/AC |
| Connection | |
| Input | 1x LAN [RJ45] 1x MAIN COM [7pin-3.81mm phoenix connector] 1x DC 24V [2pin phoenix connector] |
| Output | 1x NEXT COM [7pin-3.81mm phoenix connector, cascade output] 1x COM 1 [9pin-3.81mm phoenix connector, RS-232/422/485] 1x COM 2 [9pin-3.81mm phoenix connector, RS-232/422/485] 1x COM 3 [5pin-3.81mm phoenix connector, RS-232] 1x COM 4 [5pin-3.81mm phoenix connector, RS-232] 1x RELAY OUTPUT [8pin-3.81mm phoenix connector] |
| Mechanical | |
| Housing | Metal Enclosure — Black |
| Dimensions | 147mm [W] × 130mm [D] × 42mm [H] |
| Weight | 673g |
| Power Supply | Input: AC100–240V 50/60Hz; Output: DC 24V / 1A |
| Power Consumption (Max) | <2W |
| Operating Temperature | 0°C ~ 40°C / 32°F ~ 104°F |
| Storage Temperature | -20°C ~ 60°C / -4°F ~ 140°F |
| Operating Humidity | 20%~90% (relative humidity, non-condensing) |
Operation Controls and Functions
Front Panel

| No. | Name | Function Description |
|---|---|---|
| 1 | LAN LED (Green) | Network connection indicator — flashes when network communication is active. |
| 2 | POWER LED (Green) | On when the device is powered up. |
| 3 | RELAY LEDs (Green × 4) | Relay status indicator for each of the 4 relay channels — stays on when the corresponding relay is set to closed. |
| 4 | TX/RX LEDs (MAIN, COM1–COM4) | Data activity indicators for each serial port — red flashes on transmit (TX), yellow flashes on receive (RX). |
Rear Panel
| No. | Name | Function Description |
|---|---|---|
| 5 | DC 24V Port | DC 24V / 1A power input via 2pin phoenix connector. |
| 6 | RESET Button | Hold for 5 seconds to restore factory default settings. IP address restores to 192.168.1.100. |
| 7 | LAN Port | 10/100M network port (RJ45). Use a direct (straight-through) UTP cable — do not use a crossover cable. |
| 8 | MAIN COM Port | Main serial port for connection to a central control system or PC. 7pin phoenix connector. RS-232: PIN5=GND, PIN6=TXD, PIN7=RXD RS-422: PIN1=RX−, PIN2=RX+, PIN3=TX−, PIN4=TX+, PIN5=GND RS-485: Short PIN1(RX−)+PIN3(TX−) → B; PIN2(RX+)+PIN4(TX+) → A |
| 9 | NEXT COM Port | Main serial port cascade output — same pin-out as MAIN COM. Used to daisy-chain additional units. |
| 10 | RELAY OUTPUT Port | 4x independent, isolated, normally-open relay contacts via 8pin phoenix connector. Maximum rating: 1A / 24V DC/AC. |
| 11 | COM1 & COM2 Ports | Extended serial ports 1 and 2. 9pin phoenix connector. Support RS-232+HW Flow / RS-422 / RS-485. PIN1=RX−, PIN2=RX+, PIN3=TX−, PIN4=TX+, PIN5=GND, PIN8=RTS, PIN9=CTS |
| 12 | COM3 & COM4 Ports | Extended serial ports 3 and 4. 5pin phoenix connector. Support RS-232+HW Flow only. PIN5=GND, PIN6=TXD, PIN7=RXD, PIN8=RTS, PIN9=CTS |
Default Network & Port Settings
| IP Address | 192.168.1.100 |
| Subnet Mask | 255.255.255.0 |
| Gateway | 192.168.1.1 |
| IP Mode | DHCP OFF (static) |
| TCP/UDP Mode | TCP |
| COM1–4 TCP Ports | 8001 / 8002 / 8003 / 8004 |
| System TCP Port | 8005 |
| COM1–4 UDP Local Ports | 9001 / 9002 / 9003 / 9004 |
| System UDP Local Port | 9005 |
| COM1–4 UDP Remote Ports | 1001 / 1002 / 1003 / 1004 |
| System UDP Remote Port | 1005 |
| Main COM Baud Rate | 115200 (8 data bits, 1 stop bit, no parity) |
Application Example

Note: Use straight-through (T568A or T568B) UTP cable for the LAN connection — do not use a crossover cable. Use of a surge protection device is strongly recommended.
| Dimensions | 10 x 8 x 5 cm |
| Weight | 500g |
| Material | Premium aluminum alloy |
| Color | Black, Silver, Gold |
| Warranty | 2 years manufacturer warranty |