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
Europe Stories
05/01/2027
Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...
04/08/2026
Dalet, a leading technology and service provider for media-rich organizations, t...
04/07/2026
April 7 2026, 19:00 (PDT) Detective Conan: Fallen Angel of the Highway Opens in...
01/06/2026
January 6 2026, 05:30 (PST) Dolby Sets the New Standard for Premium Entertainment at CES 2026
Throughout the week, Dolby brings to life the latest innovatio...
11/05/2026
As Eurovision fans gear up to celebrate the 70th anniversary of the iconic song ...
11/05/2026
Pela primeira vez na hist ria, o Brasil figura entre os oito maiores mercados de...
11/05/2026
New desktop instrument focused on tactile performance
Bastl Instruments have announced the Kalimba, a new desktop instrument that combines physical modellin...
11/05/2026
Compact sampling workstation gains new features
1010music have announced the blackbox 2, a new version of their compact standalone sampler designed for DAWl...
11/05/2026
Performance-focused sequencer with microtonal control
Berlin-based KOMA Elektronik have announced Monoplex, a new 42HP Eurorack sequencer designed for hands...
11/05/2026
Boasts wireless control from mobile devices
The latest iteration of IK Multimedia's compact amp and effects modelling pedal expands on the capabilities ...
11/05/2026
Spans traditional orchestral and experimental sounds
Sonora Cinematic have recently released the third instalment in their Transfigured Orchestra series, de...
11/05/2026
Our exhibition coverage
Watch all our SUPERBOOTH 2026 video coverage in one place. Check back to this page regularly as we will be updating with more video ...
11/05/2026
aconnic AG (ISIN: DE000A0LBKW6), Munich, is participating in the Equity Forum Ge...
11/05/2026
11 May 2026
VEON Shareholders Re-elect Board and Chairman, Reaffirming Confiden...
11/05/2026
Fox Corporation Reports Third Quarter Fiscal 2026 Financial Results NEW YORK, NY, May 11, 2026 - Fox Corporation (Nasdaq: FOXA, FOX; FOX or the Company ) t...
11/05/2026
Arvato Systems Becomes a Member of InsurLab Germany
Collaboration in the insurance industrys leading innovation network
G tersloh - Arvato Systems has joine...
11/05/2026
Pirate Predator uncovers new information from victims and survivors of abuse on ...
10/05/2026
RT ALL-IRELAND DRAMA FESTIVAL WINNERS ANNOUNCED DURING GALA AWARDS STREAMED LIVE ON RTE.IE/CULTURE
Kilmeen Drama Group hailing from Rossmore, Co. Cork Scoops ...
09/05/2026
New desktop instrument focused on tactile performance
Bastl Instruments have announced Kalimba, a new desktop instrument that combines physical modelling, F...
09/05/2026
Compact sampling workstation gains new features
1010music have announced blackbox 2, a new version of their compact standalone sampler designed for DAWless ...
08/05/2026
One-button synth generates random four-track ideas
Cyma Forma and French artist Bambounou have announced RND synth, a compact hardware synthesizer built aro...
08/05/2026
Portable four-layer granular and sampling instrument
Tasty Chips have announced the GR-2, a new granular synthesizer and sampling instrument that combines e...
08/05/2026
Video Show Report
Video of SUPERBOOTH 26: Polyend Drums
Polyends big announcement for Superbooth 2026 is the Drums, a new drum machine that features both ...
08/05/2026
Deal agreed as NI enters new chapter
Native Instruments CEO Nick Williams has announced that a definitive agreement has been signed for the company to be ac...
08/05/2026
Video Show Report
Video of SUPERBOOTH 26: Erica Bullfrog Drums
The Bullfrog Drums is the latest collaboration between Erica Synths and Richie Hawtin, and ...
08/05/2026
In our latest blog, Tim Pearson reflects on the recent launch of Play Snooker, the new digital home of snooker by the World Professional Billiards and Snooker A...
08/05/2026
Pete reunites with Dogs Trust for a fourth series and a two-part overseas special
London, Friday 8th May 2026: The award winning factual entertainment series P...
08/05/2026
Wuppertal May 8, 2026
Riedel to Support Glasgow 2026 as Official Connectivity Integration Provider Riedel Communications today announced its return as a spons...
08/05/2026
ICG is excited to share news of our official launch in Northern Ireland, marking a significant milestone in the agency's growth.
Led by Digital Marketing M...
08/05/2026
Over the past ten years, Thames Water, in partnership with Arqiva, has installed more than 1.2 million smart meters, creating one of the most extensive advanced...
07/05/2026
Journalists reporting on Sudan are working in one of the most complex and fast-m...
07/05/2026
Seit dem Start im Jahr 2023 hat DJ (Beta) das personalisierte H rerlebnis von 94...
07/05/2026
Da quando stata presentata nel 2023, DJ (beta) ha aiutato a definire un'esperienza d'ascolto pi personalizzata per 94 milioni di utenti Spotify Premi...
07/05/2026
Since launching in 2023, DJ (beta) has helped shape a more personalized listenin...
07/05/2026
Desde o lan amento em 2023, o DJ (beta) j ajudou a deixar a experi ncia de ouvi...
07/05/2026
From our earliest days, Spotify has been built on a simple principle: Great audio should be easy to reach. It's what's driven us to expand from music to...
07/05/2026
Asian and Pacific Islander artists continue to shape the global soundscape, pushing creative boundaries and connecting with fans worldwide. This Asian & Pacific...
07/05/2026
Company announce long-requested choir instrument
In the latest expansion of their Symphonic Elements series, UJAM have introduced an all-new vocal instrumen...
07/05/2026
Modular-inspired sound generation with digital control
Buchla have introduced Ziggy, a new compact synthesizer built around the company's complex oscill...
07/05/2026
Combines analogue voices with digital synthesis and sequencing
Polyend have announced Drums, a new hybrid analogue and digital drum machine that combines sy...
07/05/2026
Control surface now officially supports four DAWs
When Nektar launched the Panorama CS12 control surface, it worked exclusively with Apple's Logic Pro, ...
07/05/2026
In the first quarter 2026, SGL Carbon generated consolidated sales of 184.5 million, which was 49.8 million, or 21.3%, lower than in the prior year (Q1 2025: ...
07/05/2026
Rohde & Schwarz and Greenerwave achieve precise and fast ESA antenna characteriz...
07/05/2026
January 8, 2024
Colorfront (colorfront.com), a leader in high-performance, on-s...
07/05/2026
February 9, 2024
Colorfront (colorfront.com), the multi-award-winning pioneer i...
07/05/2026
March 20, 2024
NAB 2024, Las Vegas - Colorfront (colorfront.com), the multi-awa...
07/05/2026
April 1, 2025
CINEMACON, APRIL 1, 2025 - Colorfront (colorfront.com), the multi-award-winning developer of high-performance dailies/transcoding/streaming syste...
07/05/2026
June 15, 2025
Colorfront (colorfront.com), an Academy and Emmy Award-winning de...
07/05/2026
June 15, 2025
Colorfront participated in the ICTA Barcelona Cinema Technology Summit on Sunday, June 15, 2025. Held at The Phenomena Experience, the event feat...
Applicable Products Part number Description 
