Moxa OnCell G3110 / G3150 Replacement: Direct 4G LTE Cellular Migration

Moxa OnCell G3110 / G3150 Replacement:
Direct 4G LTE Cellular Migration

Don’t let 2G/3G network shutdowns break your remote SCADA polling. Upgrade to robust 4G LTE serial cellular gateways with zero wiring modifications and transparent Modbus routing.

The 2G/3G Sunset Reality: Why Your OnCell Modems Are Going Offline

Legacy cellular gateways like the OnCell G3110 and G3150 rely on GSM, GPRS, and HSPA modules. With AT&T, Verizon, Vodafone, and Optus actively shutting down legacy cell towers, these devices are physically losing their RF signals. Firmware updates cannot fix hardware basebands.

The CGNAT Trap (Private IPs)

In the 3G era, carriers often provided static public IPs, allowing your SCADA to use “TCP Server” mode to poll the gateway. Today, 4G LTE carriers issue CGNAT (Private) IPs by default. If your replacement gateway cannot actively initiate connections (TCP Client/MQTT), your SCADA will never reach it.

The Overpriced OEM Upgrade

Upgrading to the manufacturer’s own LTE variants (like the G3150A-LTE) often introduces extreme brand premiums and volatile 16-week lead times. You need an industrial-grade Cat-1 LTE alternative that ships today without the OEM tax.

Overcoming LTE CGNAT: Keep SCADA Polling Without Proprietary Protocols

The Valtoris VT-DTU500 is engineered specifically to break through 4G carrier firewalls and keep remote assets online autonomously.

1. Active Network Penetration

The VT-DTU500 does not wait passively for SCADA pings but supports TCP Client mode and MQTT pushing. It actually punches through the CGNAT firewall from the field to your central server using strong protocols like IPsec and WireGuard VPNs. Combined with our VirCom utility, your SCADA software continues polling COM3 as if the device was locally attached.

2. Hardware-Level Link Recovery

You don’t need expensive, proprietary software like “GuaranLink” to stay online. The VT-DTU500 utilizes native ICMP Ping Detection and an independent hardware watchdog. If the LTE link drops and the ping fails, the baseband is physically reset, guaranteeing your solar arrays and lift stations never hang in a “half-open” state.

Pin-to-Pin Hardware Compatibility: DB9 & Terminal Block Ready

The Valtoris VT-DTU500 acts as a direct physical and electrical drop-in for the Moxa OnCell series. Keep your existing DIN-rails and control cabinets intact.

Engineering ParameterMoxa OnCell G3110 / G3150Valtoris VT-DTU500 Series
Cellular NetworkObsolete 2G/3G (GPRS/HSPA)Modern 4G LTE Cat-1 (Global Bands)
Serial InterfaceDB9 (RS232) / Terminal (RS422/485)Direct Match: DB9 Male (RS232) & TA/TB Terminal (RS485)
Input Voltage12 to 48 VDCCompatible: 9 to 48 VDC
Modbus HandlingBasic Transparent TCPAdvanced: Storage Modbus Gateway & Multi-Host Arbitration
CGNAT BypassRequires Static IP SIM CardsNative TCP Client, IPsec/WireGuard, & MQTT Push via DHCP
AvailabilityEOL / Extreme Lead TimesIn Stock for Immediate Global Dispatch

Software Configuration Mapping: No SCADA Rewrites

Migrating to a new hardware vendor shouldn’t require reprogramming your PLCs. Here is the exact parameter translation from Moxa’s NPort Administrator to the Valtoris Web GUI.

Legacy Moxa Setting
Operating Mode: Real COM
Valtoris VT-DTU500 Setting
VirCom: Virtual Serial Mode (Bind ID)
Legacy Moxa Setting
Operating Mode: TCP Server
Valtoris VT-DTU500 Setting
Work Mode: TCP Client + MQTT Push
(Bypasses 4G CGNAT Firewalls)
Legacy Moxa Setting
Connection Alive: GuaranLink
Valtoris VT-DTU500 Setting
Keep Alive Time (60s) + Ping Net Detect

Field Engineer FAQ: Moxa OnCell Migration

Straight answers to the technical hurdles integrators face when moving away from legacy 3G gateways.

We use Moxa OnCell G3150 in TCP Server mode. When we upgrade to 4G LTE, our SCADA master can no longer connect. Will your gateway fix this?
Yes, but the root cause is cellular carrier architecture, not just the hardware. Modern 4G LTE SIM cards usually operate behind Carrier-Grade NAT (CGNAT), meaning the gateway no longer receives a public static IP for inbound TCP Server polling. To fix this without buying expensive static APNs, our gateways support TCP Client mode, MQTT pushing, and embedded VPN tunnels (IPsec and WireGuard). The gateway actively initiates the connection from the field to your central SCADA server, bypassing CGNAT completely without rewriting your PLC code.
Moxa’s GuaranLink keeps our remote solar modems online when cell towers drop. How do your gateways prevent half-open cellular hangs?
We do not rely on proprietary, brand-locked software protocols. Our cellular gateways utilize a Multi-Tier Link Redundancy Engine: Continuous ICMP / Link-layer ping checks, automated PPP link renegotiation upon packet loss thresholds, and an independent on-board physical hardware watchdog (WDT) that cuts and re-engages power to the LTE cellular module if the baseband processor freezes. Your remote sites stay online autonomously.
Is the serial baud rate and Virtual COM driver compatible with older RTUs (like Allen-Bradley MicroLogix or Modicon)?
Yes. Our serial interfaces support all standard industrial baud rates (from 300 bps up to 921.6 kbps) with customized data bit and parity framing. If your legacy architecture relies on mapping cellular endpoints to local COM ports on a Windows server, our included VirCom Virtual COM software maps seamless virtual ports over TCP/IP over LTE.
Stop Overpaying for Basic Forwarding.
Secure advanced Modbus arbitration and robust cellular connectivity at a fraction of the cost. Test the VT-DTU500 in your own SCADA lab.
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