Overview
This guide explains how to install, connect and establish communication with a Siretta industrial modem. It covers hardware setup, SIM installation, terminal emulator configuration and the essential AT commands required to verify modem operation and network registration.
| Part Number | Description |
|---|---|
| ZETA-GEP-LTE4 (EU) | Low Power LTE Cat 4 European Modem with GPIO and GNSS |
| ZETA-NEP-LTE4 (EU) | Low Power LTE Cat 4 European Modem with GPIO |
| ZETA-N-LTE (EU) | High Performance LTE Cat 4 Modem with GPIO |
| ZETA-NSP-LTE1 (EU) | Low Power LTE Cat 1 Modem |
| ZETA-NLP-LTE1 (EU) | Ultra Low Power LTE Cat 1 Modem |
| ZETA-G-GPRS | GSM/GPRS Modem with GNSS |
| ZETA-N2-GPRS | GSM/GPRS Modem |
This guide demonstrates how to:
Expected Result
At the end of this guide the modem should be fully operational and registered on the mobile network.
| Item | Description |
|---|---|
| Siretta Industrial Modem | Compatible Siretta modem |
| SIM Card | Active SIM card with cellular service enabled |
| Cellular Antenna | Compatible antenna connected before power-up |
| USB or RS232 Cable | Depending on modem interface |
| Windows PC or Laptop | Used for modem configuration |
| Terminal Emulator | Tera Term, PuTTY or HyperTerminal |
| Power Supply | Suitable regulated modem power source |
Before advanced communication can be established, the modem must first:
Only after these steps are completed should packet data and advanced networking functions be configured.
Important Note
Always remove power before inserting or removing the SIM card to avoid SIM or modem damage.
Connect the antenna securely to the modem antenna connector.
| Recommendation | Reason |
|---|---|
| Tighten connector fully | Prevent RF loss |
| Position antenna vertically | Improve signal reception |
| Avoid metal obstructions | Reduce signal attenuation |
| Use suitable antenna type | Ensure correct frequency support |
Important Note
Never operate the modem without a cellular antenna connected.
Depending on the modem type, connect the modem using:
Apply power to the modem once all connections are complete.
Most Siretta modems create one or more virtual COM ports when connected to Windows.
| Device | Example COM Port |
|---|---|
| USB Serial Port | COM3 |
| Modem Interface | COM4 |
| Diagnostic Interface | COM5 |
Important Note
The AT command interface is usually the primary modem COM port rather than the diagnostic interface.
| Setting | Value |
|---|---|
| Bits per second | 115200 |
| Data bits | 8 |
| Parity | None |
| Stop bits | 1 |
| Flow control | Hardware |
Open Tera Term, PuTTY or HyperTerminal and connect to the identified COM port.
Expected Result
The terminal window should open without connection errors.
The AT command confirms communication between the PC and modem.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT |
| Command | Description |
|---|---|
AT |
Basic modem attention command |
| Possible Cause | Action |
|---|---|
| Incorrect COM port | Verify Device Manager |
| Incorrect baud rate | Confirm terminal settings |
| Flow control issue | Verify hardware flow control |
| Faulty cable | Replace or reconnect cable |
| Modem not powered | Verify power supply |
Expected Result
The modem should returnOK.
The ATI command displays modem identification information.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
ATI Manufacturer: Telit |
| Information | Description |
|---|---|
| Manufacturer | Modem vendor |
| Model | Modem hardware platform |
| Revision | Installed firmware version |
Expected Result
The modem should return manufacturer, model and firmware information.
The modem can confirm whether the SIM card has been detected successfully.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CPIN? |
| Response | Meaning |
|---|---|
READY |
SIM operational |
SIM PIN |
SIM requires PIN entry |
SIM PUK |
SIM locked |
SIM NOT INSERTED |
SIM not detected |
Expected Result
The modem should return+CPIN: READY.
Once the SIM is operational, the modem must register on the mobile network.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CREG? |
| Response | Meaning |
|---|---|
0,1 |
Registered on home network |
0,5 |
Registered while roaming |
0,2 |
Searching for network |
0,3 |
Registration denied |
| Problem | Possible Cause |
|---|---|
| Searching continuously | Weak signal |
| Registration denied | SIM issue or unsupported network |
| No registration | Antenna or coverage issue |
Expected Result
The modem should return either0,1or0,5.
The modem signal level can be checked using the AT+CSQ command.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CSQ |
| Signal Value | Signal Quality |
|---|---|
| 0 - 9 | Poor |
| 10 - 14 | Fair |
| 15 - 19 | Good |
| 20 - 31 | Excellent |
Important Note
Poor signal strength may cause network registration failures or unreliable data communication.
Some Siretta modems include status LEDs to indicate modem operation.
| LED State | Typical Meaning |
|---|---|
| Solid RED LED | Modem powered |
| Fast flashing RED LED | Searching for network |
| Slow flashing RED LED | Registered on network |
Important Note
LED behaviour may vary between modem models.
| Problem | Possible Cause | Solution |
|---|---|---|
| No COM port detected | Driver issue | Reinstall drivers |
| No modem response | Incorrect serial settings | Verify baud rate and flow control |
| SIM not detected | Incorrect SIM insertion | Reinsert SIM |
| No network registration | Weak signal | Reposition antenna |
| Frequent disconnects | Power instability | Verify power supply |
| Step | Action |
|---|---|
| 1 | Insert the SIM card |
| 2 | Connect the antenna |
| 3 | Connect the modem to the PC |
| 4 | Identify the correct COM port |
| 5 | Configure the terminal emulator |
| 6 | Verify modem communication |
| 7 | Verify SIM operation |
| 8 | Verify network registration |
| 9 | Verify signal strength |
After completing this guide the modem is now ready for:
Next Guide
Continue with the "Core Modem Functions" guide for modem configuration, packet data activation and operational AT commands.
Support
For further assistance, please contact the Siretta support team.