Applicable Products Part number Description
ZETA-GEP-LTE4 (EU) Low Power LTE Cat 4 European Modem with GPIO and GNSS
ZETA-G-GPRS Entry Level GPRS Modem with GNSS (GL)
ZETA-N2-GPRS Entry Level GPRS Modem (GL)
ZETA-NEP-LTE4 (EU) Low Power LTE Cat 4 European Modem with GPIO
ZETA-NEP-LTEM (GL) Low Power Global LTE Cat M Modem with GPIO
ZETA-NLP-LTE1 (EU) Ultra Low Power European LTE Cat 1 Modem
ZETA-NLP-LTEM (GL) Ultra Low Power Global LTE Cat M Modem
ZETA-N-LTE (EU) High Performance LTE Cat 4 Modem with GPIO
ZETA-NSP-LTE1 (EU) Low Power European LTE Cat 1 Modem
Objective Once a Siretta ZETA modem is powered on, a combination of its 3 LEDs light up, showing different stages of modem connection to a network (default state).
Also, assuming the network connection is achieved, the modem can send a receive AT commands.
If any of the above fails to materialise, a troubleshooting procedure will help to investigate and solve basic issues.
Solution This application note covers the following:
No LED indication
Modem keeps rebooting
Failure to connect to a modem serial port
No response from the modem when using AT commands
No Carrier when dialling Voice/ data calls
Demonstration of Solution LEDs Not Lit
Check the modem has been connected to the correct power supply
Check the power connector is inserted correctly
Check the power has been switched on at the mains
Check the LED functionality has been set with either AT#SLED or AT#GPIO AT commands
Modem Reboot If your Siretta modem keeps rebooting, please check the following procedures:
Check the SIM card has been inserted correctly
Check the power supply is correctly specified or you are using an approved Siretta PSU.
No Serial Connection If your Siretta modem has no serial connection, please check the following procedures:
Check the serial cable has been inserted correctly
Check the serial cable has the correct pin alignment (see below)
Check the modem emulator program has the proper settings (Factory settings = 115200, 8, n, 1)
Check there isn't another program interfering with the communication program
Check there isn't a conflict with communication port access
RS232 Serial Port Interface This connector provides serial RS232 communication between ZETA-xxP modem and the connected equipment. The modem can be configured via the RS232 connection using AT commands as specified in the AT command manual.
Table 15. Pins Usage
Pin Name Usage Status Direction
1 DCD Output from UART that indicates the carries is present Connected OUT
2 RXD Output transmit line of UART Connected OUT
3 TXD Input receive line of UART Connected IN
4 DTR Input to UART and controls DTE ready condition
Connected IN
5 GND Ground
Connected IN
6 DSR Output from UART that indicates the module is ready
Connected OUT
7 RTS Request to Send - Input line of UART that controls hardware flow control
Connected IN
8 CTS Clear to Send - Output line of UART that controls hardware flow control
Connected OUT
9 RI Ring Indicator- Output line of UART that indicates the incoming call condition
Connected OUT
Supported baudrates
>> 2400 >> 38400
>> 4800 >>57600
>> 9600 >>115200
>> 19200 >230400
No Carrier Message If your Siretta modem returns a No Carrier' message upon an attempted call (voice or data), please consider the following possible causes:
If the modem returns Then ask? Action
No Carrier' Is the received signal strong enough? Use AT+CSQ' to check RSSI.
Check signal strength indication. *
Is the antenna connected correctly? Ensure antenna is firmly screwed into place.
No Carrier'
(When trying to issue voice communication) Is the semicolon ( ; ) entered immediately after the phone number in the AT command? Ensure that the semicolon ( ; ) is entered after the phone number in the AT command. (e.g. ATD123456:)
No Carrier'
(When trying to issue data communication) Is the SIM card configured for data/fax call? Configure the SIM card for data/fax calls. (Ask your network provider if necessary)
Is the selected bearer type supported by the called partly? Ensure the selected bearer type is supported by the call party.
Is the selected bearer type support by the network? Ensure the selected bearer type is supported by the network.
If no success, try bearer select type by AT COMMAND: AT+CBST=0,0,3'
Value of RSSI Interpretation
0 to 12 Insufficient or weak
13 to 19 Average
20-31 Good
99 No Signal
Additional Reading Description Author
ZETA Hardware user's manual Siretta
AT command manual Telit
Quick Start Guide Siretta
Post Views: 32
Most recent headlines
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
17/12/2025
KPop Demon Hunters Stars Visit Berklee for Weeklong Celebration Andrew Choi and EJAE, who voiced the film's main characters and contributed to its soundtr...
16/12/2025
Hawkins has landed on Spotify, just in time for Stranger Things Season 5, Volume...
16/12/2025
Wherever you are, your favorite music and audio content should go seamlessly with you. That's why Spotify has partnered with NAVER Corp, Korea's leading...
16/12/2025
2025 Wrapped arrived bigger and bolder than ever. This year's experience is designed to be ultra personal and shareable, with new features like Wrapped Part...
16/12/2025
Three 12-kilowatt Advanced Electric Propulsion System thrusters, supplied by L3Harris Technologies, form the core of Gateway's propulsion system. Pictured i...
16/12/2025
The challenge facing America's defense industrial base is not just about speed - its about rebuilding the foundation that makes speed possible. Our nations ...
16/12/2025
Share Share by:
Copy link
Facebook
X
Whatsapp
Pinterest
Flipboard...
16/12/2025
SEVILLE, Spain Canal Sur, the public broadcasting service for Andalusia, Spain, has completed a total technology refresh based on Pebble's resilient, softwa...
16/12/2025
NEW YORK Teleprompting hardware provider Telescript International has acquired all software code and intellectual property previously owned by Telescript West. ...
16/12/2025
As cable operators face increased competition from 5G fixed wireless access providers, a new report from Ookla Research finds that T-Mobile is the FWA speed lea...
16/12/2025
Apple has announced a major upgrade to the Apple TV app for device owners outside the Apple ecosystem with news that the Apple TV app for Android now supports G...
16/12/2025
Space42 grows Direct-to-Device partner ecosystem through a Memorandum of Underst...
16/12/2025
16 Dec 2025
VEON Announces Release Date for Full Year and Fourth Quarter 2025 R...
16/12/2025
16 Dec 2025
VEON's Kyivstar Invests in Renewable Energy in Ukraine with Acq...
16/12/2025
Back to All News
Emma Appleton, Fares Fares, Frida Gustavsson and Jakob Oftebro...
16/12/2025
Back to All News
Docu-reality My Korean Boyfriend Gets a Trailer and Premiere D...
16/12/2025
Harmonic's XOS Advanced Media Processor Improves Streaming Video Quality and Boosts Viewer Engagement SAN JOSE, Calif. - Dec. 16, 2025 - Harmonic (NASDAQ: ...
16/12/2025
RT Sport Awards 2025 live on RT One and RT Player at 8:05pm on Saturday 20 December.
On Saturday 20 December live on RT One and RT Player at the earlier t...
16/12/2025
Singer -songwriter Brian Kennedy has been announced as the final celebrity dance...
15/12/2025
Harlem Globetrotters Celebrate 100th Anniversary With New Brand Campaign From Th...
15/12/2025
Top L-R: La Tierra Del Valor (The Home of the Brave), Mangittatuarjuk (The Gnawe...
15/12/2025
L3Harris will leverage 15 years of experience supporting the E-4B Nightwatch and...
15/12/2025
CONWAY, Ark. In a notable example of how the loss of federal funding is forcing public stations to make massive cuts and operational changes, the statewide pub...
15/12/2025
BOULDER, Colo. Public Media Venture Group (PMVG), Venture Technologies Group (VTG), and WQED have completed a multipart agreement that they say will significant...
15/12/2025
Cape Town, November 13, 2025 - SES and International artist and humanitarian, Fo...
15/12/2025
Luxembourg, December 15, 2025 - SES, a leading space solutions company, and Abra Group launched fast and reliable multi-orbit inflight connectivity service on t...
15/12/2025
How Rivian s Design Puts Drivers First-And Why That Matters Published on Dec 15, 2025 Categories: Business Solutions
LinkedIn Corporate Communications
Sha...
15/12/2025
Space42 and Cobham Satcom completed the full range of advanced terminals for the...
15/12/2025
15 Dec 2025
VEON's Beeline Kazakhstan Delivers First Starlink Direct to Cel...
15/12/2025
Andrew Mountbatten-Windsor finds himself the topic of year's cracker jokes
Oasis, David Harbour, Celebrity Traitors and Angela Rayner all feature in this y...
15/12/2025
Comscore Expands Cross-Platform Campaign Measurement to Include Audio and Social New capabilities strengthen cross-platform campaign reporting suite; CCR rebran...
15/12/2025
NVIDIA today announced it has acquired SchedMD - the leading developer of Slurm, an open-source workload management system for high-performance computing (HPC) ...
15/12/2025
RT .ie has reached one billion page views this year and is on track to finish 2025 2% ahead of last year. Average time spent on the site is up 3% on 2024, with ...
15/12/2025
Modern workflows showcase the endless possibilities of generative and agentic AI on PCs.
Of many, some examples include tuning a chatbot to handle product-supp...
13/12/2025
Powering Client Growth: Horizon Deepens Nielsen Partnership, Enabling More Effic...
13/12/2025
In a move that will help it offer more flexible and less costly programming options, YouTube TV has announced that it will be launching YouTube TV Plans with mo...
13/12/2025
SINGAPORE Magna Systems has designed, built and completed what is believed to be the first full UHD and IP-based OB truck in Southeast Asia for a Singapore medi...
12/12/2025
SVG Summit 2025 Preview: Everything You Need to Know for Next Week's Big Sho...
12/12/2025
Hailey Gates at the Atropia premiere (photo by George Pimentel / Shutterstock for Sundance Film Festival)...
12/12/2025
Last month, Spotify announced a new collaboration with the ATP Tour, the global governing body of men's professional tennis, aimed at bringing the next gene...
12/12/2025
CONWAY, Ark. In a notable example of how the elimination of Federal federal funding is forcing public stations to make massive cuts and changes in the way they...
12/12/2025
Wisycom and DPA Microphones announce the appointment of Ren Moerch as Group Product Director, Wireless, a strategic leadership role that will guide the combine...
Applicable Products Part number Description 
