ZSM-4G-USB
4G adapter with USB connector for remote monitoring of ZCS Azzurro inverters where there is no Wi-Fi coverage or network socket at the installation point.
It includes a virtual SIM built into the device with data traffic already covered for 10 years: no subscription to activate, no card to insert. Production data refreshes on the ZCS app and portal every 5 minutes.
The ZCS Azzurro ZSM-4G-USB is the 4G monitoring adapter that connects a solar inverter to the ZCS Azzurro portal and app over the cellular network. It is the answer for installations where the board or inverter sits far from the house router, in plant rooms, cellars or rural buildings where Wi-Fi does not reach and running a network cable is not practical.
USB or EXT: the check to make before ordering
This is the most frequent mistake on this item. ZCS produces two families of 4G adapter with physically different connectors and separate compatibility lists:
- ZSM-4G-USB (this product): USB connector, for inverters that expose the dedicated USB port
- ZSM-4G-EXT: a different external connector, for another inverter series
The two are not interchangeable. Before ordering, check the exact inverter model and the type of connector on the front or underside of the unit.
Compatible ZCS Azzurro inverters
The ZSM-4G-USB is intended for the following families:
- Single-phase 3000-6000 TLM-V3
- Three-phase 3.3-12 KTL-V3, 15000-24000 TL-V3, 25-50 KTL-V3, 60-80 KTL-V3
- Three-phase 80-110 KTL-LV, 100-136 KTL-HV, 100-110 KTL-V4, 250/255 KTL-HV
- Single-phase hybrids 1PH HYD 3000-6000 ZSS HP and 1PH HYD 3000-6000 ZP1
- Three-phase hybrids 3PH HYD 5000-20000 ZSS
If you are unsure about your model, check the ZCS monitoring systems datasheet or contact us before purchasing.
ZSM-4G-USB technical specifications
| Type | 4G monitoring adapter with USB connector |
| Connectivity | 4G cellular network |
| SIM | Virtual, built into the device |
| Data traffic included | 10 years |
| Update interval | Every 5 minutes |
| Platforms | ZCS Azzurro app (Android and iOS) and web portal |
| Installation | Plug-and-play into the inverter USB port |
| Alternative version | ZSM-4G-EXT (different connector and compatibility) |
What you can monitor
The app and portal show instantaneous and cumulative production, daily, monthly and annual charts, operating status and inverter alarms. On systems with storage and a meter, consumption, energy flows and battery state of charge are added. For the installer the practical benefit is remote diagnosis: many jobs are closed without a site visit.
Frequently asked questions
Do I have to pay a subscription for the data connection?
No. The device is supplied with a built-in virtual SIM and the data traffic fee already covered for 10 years, sized for transmitting inverter monitoring data. There is no contract to activate and no SIM of your own to insert.
What is the difference between ZSM-4G-USB and ZSM-4G-EXT?
The connector and the list of compatible inverters. The USB version plugs into the dedicated USB port found on certain series, while the EXT version uses a different external fitting provided on other series. They are not interchangeable, so check the exact inverter model before ordering.
Can I use it if I already have Wi-Fi at home?
You can, but if the Wi-Fi signal reliably reaches the inverter, the Wi-Fi stick is usually the cheaper choice. 4G makes sense when the signal is weak or absent at the installation point, when the home network is unstable, or when the system is in a building with no internet connection.
How often is the data updated?
Data refreshes automatically every 5 minutes on the ZCS app and portal. That granularity is fine for following production and receiving alarms, but it is not the same as instant-by-instant real-time reading.
Does installation require a technician?
Physically fitting the adapter is plug-and-play into the inverter's dedicated port. Subsequent configuration requires registering the installation on the ZCS portal with the serial numbers of the inverter and the device. The work should still follow the safety procedures required for accessing the inverter.