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UDPTCP Industrial Firewall PC
Industrial firewall · 4× 2.5GbE · 2× RS232 · 8 GPIO · barebone

UDPTCP Industrial Firewall PC

The CX-N100-2C-4L is a four-port N100 router with industrial I/O bolted on: two RS232 ports, eight GPIO lines, a nano SIM tray and a mini PCIe slot for a 4G modem, on a 10-layer board. It ships barebone.

  • ProcessorIntel N100, 4 cores, up to 3.4GHz, 6W TDP
  • Network4× 2.5GbE, Intel i226-V or i225-V
  • Industrial I/O2× RS232, 8 GPIO (4 in, 4 out)
  • CellularMini PCIe for Wi-Fi or 4G, nano SIM
  • Memory1× DDR4 SO-DIMM 3200MHz, not included
  • StorageM.2 Key-M (PCIe or SATA) + SATA 3.0, not included
Buy it for
  • A router or gateway in a control cabinet with serial equipment
  • 4G failover built into the firewall
  • Remote sites that need GPIO alarms or relay outputs
Skip it for
  • A quiet living-room router with no serial needs
  • Buyers who want memory and storage included
See today’s price

Its ports are i226-V or i225-V, so ask which you get

UDPTCP specifies the four 2.5GbE ports as Intel i226-V or i225-V, meaning either controller may be fitted. Both are Intel 2.5GbE chips, both use the same igc driver on FreeBSD and Linux, and both work with OPNsense, OpenWrt and ESXi. The difference is in history.

Early i225-V steppings had well-publicised link and packet-loss problems at 2.5GbE, fixed in later revisions. The i226-V is the successor and the chip router builders now ask for. A box fitted with a late-revision i225-V is fine; the point is to know which you have.

  • i226-V: the current chip, native in pfSense 2.7+ and OPNsense 22.1+.
  • i225-V, late stepping: works well on current releases.
  • i225-V, early stepping: the one to avoid for a 2.5GbE WAN.
Ask before ordering. Confirm with UDPTCP which controller ships, and if it is the i225-V, which revision. On Linux, lspci -vv shows the controller and revision once the box arrives.

Whichever chip is fitted, each port sits behind an RJ45 jack with integrated filtering. If a port drops link intermittently, disabling Energy Efficient Ethernet on that interface is the usual first fix on both generations.

For routing itself, four ports cover the standard plan: WAN, LAN, a guest or IoT segment, and a spare for a DMZ or second WAN. The four Gracemont cores handle NAT and a sensible rule set on a 1Gbit/s or 2.5Gbit/s line; deeper inspection with Suricata is where they start to work hard. More four-port layouts sit under N100 firewall mini PCs.

Hardware

What’s inside

SpecValue
ModelCX-N100-2C-4L
ProcessorIntel N100, 4 cores / 4 threads, up to 3.4GHz, 6MB cache
TDP6W
GraphicsIntel UHD Graphics
Memory slot1× DDR4 SO-DIMM, 3200MHz
M.21× M.2 Key-M 2280 (2242 on request), PCIe or SATA SSD
SATA1× SATA 3.0, 6Gbps
Mini PCIe1× for Wi-Fi or 4G; can be set to mSATA in hardware
SIM1× nano SIM
Ethernet4× 2.5GbE, Intel i226-V or i225-V, filtered RJ45 jacks
VideoHDMI + DP, dual 4K@60Hz
USB2× USB 3.0, 4× USB 2.0
Serial2× RS232 COM
GPIO8 lines: 4 inputs, 4 outputs
BIOSAMI EFI; PXE boot, Wake-on-LAN, auto power-on
Board10-layer PCB
Supported systemsOPNsense, OpenWrt, Linux, Windows, ESXi
ConfigurationBarebone: no RAM, no SSD

Two RS232 ports and 8 GPIO for control-cabinet work

Most firewall boxes stop at Ethernet and USB. This one adds two RS232 serial ports and eight GPIO lines, four inputs and four outputs, on a 10-layer circuit board. That puts it in a different category: a router that can also talk to equipment and react to physical signals.

RS232 is still everywhere in industrial and network gear. Switches, UPS units, PLCs, meters and older controllers expose serial ports for configuration or data. With two of them on the router, one can serve as the box's own console and the other can reach a device beside it.

  • Console access: manage the router over a serial cable when the network config is broken.
  • Out-of-band management: reach a switch's serial console remotely through the router.
  • Serial-to-network gateway: bridge a Modbus RTU device or a meter onto the network with Linux tools.
  • UPS monitoring: read an older serial-only UPS for clean shutdowns.

The GPIO lines take the same idea to physical signals. Inputs can read a cabinet door switch, a flood sensor or a UPS alarm contact. Outputs can drive a relay, a warning light or a reset line to another device, from scripts on the router.

Check the voltage levels. GPIO on boards like this runs at logic levels, not 12V or 24V industrial signals. Put an opto-isolator or relay module between the header and anything in the field.

The 10-layer PCB is a build-quality detail. More layers give cleaner power and ground planes, which helps a board that sits in an electrically noisy cabinet next to motors and contactors.

Market position

How it fits the lineup

N100 mini PC models by type, September 2026. Highlighted: UDPTCP Industrial Firewall PC.

A nano SIM tray and a mini PCIe slot for 4G failover

A mini PCIe slot takes a Wi-Fi card or a 4G modem, and a nano SIM tray sits beside it. At a remote site with no second wired line, that is the failover link. The slot can also be switched to mSATA at the hardware level, for an extra SSD instead of a radio.

OpenWrt supports most common mini PCIe modems through QMI or MBIM. OPNsense and pfSense treat them as PPP interfaces, which works but asks for more manual setup. Match the modem's chipset to the OS before buying it, and choose a card certified for your carrier.

SlotTakesNotes
M.2 Key-M2280 PCIe or SATA SSD2242 length available on request
SATA 3.02.5-inch SSD or HDD6Gbps
Mini PCIe4G modem, Wi-Fi card, or mSATAmSATA needs the hardware option
SO-DIMMDDR4, 3200MHzOne slot, single channel

Memory is one DDR4 SO-DIMM at 3200MHz, and the N100 is specified for up to 16GB. For a gateway, 8GB is plenty. The M.2 slot adapts to PCIe or SATA drives, so almost any 2280 SSD in a drawer will boot it.

Antenna placement decides how well the 4G link works. A metal cabinet blocks signal, so route the modem's antenna leads to bulkhead connectors on the outside of the enclosure.

  1. Fit a DDR4 SO-DIMM and an M.2 2280 SSD.
  2. Add a 4G modem card and data SIM if the site needs failover.
  3. Enable auto power-on in the AMI BIOS so the box restarts itself after an outage.
  4. Set PXE or Wake-on-LAN only if the site's management tools use them.
Other options

Three other routes

The CX-N100-2C-4L next to Dozlzyp's COM build and oaknode's LTE box

This box earns its place through I/O, not networking. Plenty of four-port routers share its core layout. Few combine serial ports, GPIO and a SIM slot on one board, and that trio is what this box sells on.

The Dozlzyp X4C-XL has a build with two COM ports, TPM 2.0 and a fanless aluminium case, but no GPIO or SIM. The oaknode MGNASN has an LTE slot, SIM and GPIO plus two 10GbE SFP+ cages, at the cost of more complexity. UDPTCP's own six-port box trades the industrial I/O for two more 2.5GbE ports.

  • Pick the CX-N100-2C-4L for serial devices, GPIO signals and 4G on one board.
  • Pick Dozlzyp for serial console access in a silent, fanless case.
  • Pick oaknode if 10GbE fibre matters as much as LTE.

UDPTCP does not state a cooling method for this model. For a cabinet install, check whether a fan is fitted and plan airflow either way; industrial enclosures trap heat. Idle draw depends on linked ports, the SSD and any modem card; hedged figures for firewall boxes are under N100 power consumption.

HDMI and DisplayPort both drive 4K@60Hz, and six USB ports, two of them USB 3.0, cover a keyboard, a backup drive and a USB-to-serial adapter if two RS232 ports ever run out. On a headless gateway those outputs mostly matter on install day and during rescue work.

Pin down the NIC chip and revision, and choose between 2280 and 2242 SSD length. Budget for a modem card, antennas and an isolator module if GPIO will touch field wiring. Chip-level limits, including memory, are listed under N100 specs.

FAQ

Owner questions

Which network chip does the UDPTCP industrial firewall use?

Its four 2.5GbE ports use either Intel i226-V or i225-V controllers. Ask UDPTCP which ships, and the revision if it is an i225-V.

Can it take a 4G SIM?

Yes. It has a nano SIM tray and a mini PCIe slot for a 4G modem card, which is a separate purchase.

What are the GPIO lines for?

Eight lines, four inputs and four outputs, for reading sensors such as door or alarm contacts and driving relays or lights from scripts.

Does it include RAM and an SSD?

No. Add one DDR4 SO-DIMM and an M.2 2280 SSD, PCIe or SATA.