On the M2M device side, a Four-Faith catalog split the cellular IP-modem family (F2X16 DTU, F2X03, F1X03, F-IM100) and the industrial 4G/5G router family (F3X24, F3X25, F3X26, F3X27, F3X34, F3X36, F3X46, F7X25, F7X34, F7X36, F7X46, F3X26-TB) into two separate product trees as of 2026-07-06 [S2].
That taxonomy matters: it reflects how M2M OEMs in the Chinese industrial-communications market physically package, certify and price the two functions, even when both end up talking LTE Cat 1 / Cat 4 to the same APN [S1][S3].
Functional Scope: Router = LAN + Routing + VPN; DTU = Serial-to-IP Bridge
The F3X24 industrial router is documented with one Ethernet path, one RS-232/485 port, and an NTP/RTC-embedded, multi-online-trigger feature set, placing it at the lower edge of the router family rather than the DTU family [S3]. The F2X16 4G Data Terminal Unit (DTU) and F2X03 IP Modem sit in a separate branch that carries APN/VPDN, SMS, dial-up and CSD as headline features, not LAN switching or VPN tunneling [S1].
The F1X03 industrial modem explicitly supports 2G/3G with a single DB9 RS-232 port and APN/VPDN / SMS / dial-up / CSD operation, which is the canonical DTU profile: one serial asset in, one IP tunnel out, no LAN [S2]. By contrast, the higher-end 4G Wireless Router line in the same product tree offers 4×LAN, 1×2.4 GHz Wi-Fi, 1×RS-232 or RS-485, and VPN server/client with multiple WAN access methods [S2]. That delta — LAN count, Wi-Fi, VPN client/server — is the single biggest differentiator a buyer will feel in the field.
Port Count and Topology Comparison
The 4G Wireless Router SKU is speced at 4×LAN, 1×2.4G Wi-Fi, 1×RS-232 or RS-485, with VPN server & client, multiple WAN access methods, optional GPS and APN/VPDN [S2]. The LTE Router SKU collapses that to 1×LAN, 1×RS-232 or RS-485 with NTP/RTC, DDNS and multiple online-trigger ways, but no listed Wi-Fi [S2]. The Port Router variant keeps a single LAN and adds 1×2.4G Wi-Fi plus NTP/RTC, PPPoE/DHCP server and multi-online triggers [S2]. The Dual-SIM Router adds a second SIM socket on top of the 4-LAN/Wi-Fi/serial platform [S2].
On the DTU side, the F1X03 industrial modem ships a single DB9 RS-232 only, with APN/VPDN, SMS, dial-up and CSD as the only documented service features [S2]. The ZigBee IP Modem F8X14 mixes it up with 1×RS-232, 1×RS-485, 5×GPIO and RS-422 plus DDNS, IP access and APN/VPDN, but no LAN/Wi-Fi stack [S2]. The pattern is consistent: DTU class = serial or low-density GPIO, router class = LAN/Wi-Fi + routing intelligence.
Cellular Generation and SIM Strategy
Router SKUs span 2G, 3G, 4G LTE on most F3X-line models, with the F3X27 listed as a 5G industrial router and the F3X26-TB explicitly named as an industrial LTE router [S1]. The Dual-SIM class (F3X32, F3X46, F7X46) adds cellular link redundancy on top of the 4G/3G modem core [S1][S2].
DTU SKUs cluster lower on the generation curve. The F1X03 industrial modem is speced for 2G/3G only, which already disqualifies it from a new LTE-M or NB-IoT migration project [S2]. The F2X16 4G Data Terminal Unit is the first DTU in the family that explicitly carries a 4G radio, and the F-IM100 IP Modem is positioned as the current-generation IP-modem line, not as a router replacement [S1]. If the application is LTE Cat 1/Cat 4 with planned 5G redundancy, you are inside router territory; if the asset is a legacy PLC on 2G fallback, a DTU is the cheaper, simpler answer.
Application Fit: Who Needs a Router, Who Needs a DTU
The router family maps directly onto multi-asset sites: ATM and finance, smart grid, oil and gas, water and wastewater, environmental, transportation and LoRa-applied IIoT networks all use the 4G/5G router or 5G CPE form factor for site-wide IP backhaul [S2]. The F7X36 GPS 6-port router and F7X46 GPS + Dual-SIM Wi-Fi router are designed for vehicle or remote-asset deployments where location, dual cellular failover and 4-LAN switching all have to live in one box [S1].
The DTU family maps onto single-asset retrofits: an electricity meter, a flow computer, an RTU on a pad site, a small pump station where one RS-232/485 device has to ride cellular back to a SCADA master. Four-Faith's solutions list treats the DTU as the bridge for ATM and finance, smart grid, oil and gas, water and wastewater and transportation endpoints that are essentially one-serial-asset-per-site [S1][S2]. If you find yourself adding a network switch behind a DTU to serve more than one IP endpoint, the spec has drifted out of the DTU envelope and you should be sizing a router instead.
Selection Criteria: Build vs Buy Logic
Choose an industrial router when the requirement list contains any of: more than one Ethernet endpoint, Wi-Fi client or AP, VPN server/client, dual-SIM cellular failover, GPS plus routing, or 5G readiness with LTE fallback. The F3X46 dual-SIM router and the F3X27 cellular / 5G industrial router are the reference points for that envelope [S1].
Choose an industrial modem (DTU) when the requirement list is: a single RS-232 or RS-485 asset, transparent TCP/UDP or Modbus TCP to serial tunneling, APN/VPDN private network, SMS or CSD wake-up, and no LAN or Wi-Fi. The F2X16 4G DTU and F1X03 industrial modem define that envelope, and the F-IM100 IP Modem is the current-generation refresh of the same line [S1][S2].
Pick neither blindly off the catalog page; the operational envelope of an industrial router — wide-temp metal housing, EMC immunity, DIN-rail or wall mount, watchdog hardware — is not automatic on a DTU, and the converse is also true. Buyers comparing industrial modems against routers should lock the port count, the cellular generation, the SIM strategy, and the VPN/firewall requirement as separate line items on the datasheet review before price.
Wireless-Module Adjacent Stack
Routers and DTUs are not standalone boxes in the M2M stack; they sit on top of an industrial wireless module layer that carries the actual radio. For buyers who want the underlying module selection logic — LTE Cat 1 vs Cat-M vs NB-IoT vs 5G RedCap — the Industrial Wireless Module Selection map walks through the same kind of decision matrix at the module level, and is the natural pre-cursor read before choosing between an F3X-series router and an F2X-series DTU. [S2]
The same Four-Faith catalog also packages 5G CPE, LoRa/NB-IoT/ZigBee modules, M-Bus gateways, an intelligent IoT video surveillance system and IP cameras under the same industrial-grade umbrella, all designed for harsh-environment operation per the vendor's 2026-07-06 product page [S2]. For engineers looking at price as the deciding variable, the Industrial Wireless Module Price & Cost Guide lays out the per-unit cost curve that drives router vs DTU BOM decisions, especially when the DTU's simpler BOM and lower RF complexity make it the cheaper end of the same vendor's portfolio.
Trackable next signal: how the F2X16 4G DTU and F-IM100 IP Modem lines refresh their 2G/3G fallback options as global 2G/3G sunsets progress through 2026-2027, and whether the F3X-series router family widens its 5G RedCap coverage below the F3X27 flagship. Both moves will determine whether DTU buyers stay inside the F2X-line or get pulled up into router SKUs by the time the next LTE-M refresh cycle lands.
Component reference pages worth checking: industrial adhesive.