
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
Investigative journalists across the Western Balkans and T rkiye continue to con...
17/12/2025
Sports Broadcasting Hall of Fame Inducts 10 Industry Icons During Unforgettable ...
17/12/2025
ESPN to Debut MNF Playbook with Next Gen Stats, a New AI-Driven NFL Data-AltCastThe series, powered by Adrenaline TruPlay AI, launches Dec. 22 and runs through ...
17/12/2025
Inaugural Optum Golf Channel Games Debut Under the Lights' in Primetime on ...
17/12/2025
The right playlist is essential on New Year's Eve, building the energy as you get ready and keeping it high as you count down to midnight. This year, Spotif...
17/12/2025
eds3_5_jq(document).ready(function($) { $(#eds_sliderM519).chameleonSlider_2_1({...
17/12/2025
Audiences Watched Over 103 Billion Minutes of TV on Thanksgiving Day
NFL Games ...
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
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...
17/12/2025
Wednesday 17 December 2025
Heated Rivalry will be coming to Sky and streaming service NOW on 10 JanuaryTurn on cookies to view this content. Go to Privacy opti...
17/12/2025
Back to All News
Inside The Unseen World Of Indian Customs: Netflix Reveals The...
17/12/2025
Back to All News
Netflix announces PAPARAZZI KING: the docu series coming to Ne...
17/12/2025
Back to All News
Netflix Unveils First Look at Jo Nesbo's Detective Hole Pr...
17/12/2025
Back to All News
Netflix Welcomes Warner Bros. Discovery Board Recommendation
Business
17 December 2025
Global
Link copied to clipboard
After Careful Revi...
17/12/2025
RT has announced that Kathy Fox has been appointed Commissioning Editor with re...
17/12/2025
The Hao AI Lab research team at the University of California San Diego - at the forefront of pioneering AI model innovation - recently received an NVIDIA DGX B...
17/12/2025
Editor's note: This post is part of Into the Omniverse, a series focused on ...
17/12/2025
With the new season of Dancing with the Stars shimmering in the not-too-distant future this New Year, the celebrity and dancer pairings of the twelve couples ha...
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...