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
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...
07/05/2026
Journalists reporting on Sudan are working in one of the most complex and fast-m...
07/05/2026
Multi-year partnership positions Victory+ as a free home for Dallas Cowboys orig...
07/05/2026
From sideline reporting to directing and producing, the talented sophomore is building a well-rounded foundation for a career in live sports production
In the ...
07/05/2026
Cobalt Digital has received two Future Best of Show awards at NAB Show 2026. The COBALT blueCORE platform was recognized by TV Tech, and the COBALT PACIFIC ULL-...
07/05/2026
ESPN analyst Mina Kimes will host the televised semifinals and finals of the 202...
07/05/2026
Bitmovin has announced that MUBI, the global film streaming platform, has selected Bitmovin as its cloud VOD encoding partner. Bitmovin's encoding infrastru...
07/05/2026
NBCUniversal Telemundo Enterprises and the U.S. Soccer Federation have announced...
07/05/2026
Angel City Football Club (ACFC) and Victory have announced a regional broadcast partnership bringing live match coverage to fans across the greater Los Angeles...
07/05/2026
Spiideo has announced the launch of AI Highlights inside Spiideo Play, its automated sports production platform. AI Highlights combines video, event data, audio...
07/05/2026
Leostream Corporation has announced a unified remote access ecosystem for high-p...
07/05/2026
The Atlanta Dream has partnered with Victory to stream all locally broadcast Dream games for free, expanding the team's digital distribution strategy and g...
07/05/2026
Riedel Communications has announced the appointment of Marc Engroff as Chief Fin...
07/05/2026
SES and ARD, Germany's largest public broadcasting network, have announced a long-term extension of their satellite distribution partnership through 2039. U...
07/05/2026
UpLight Technologies delivers a flexible video and lighting system for a new televised sportLaunching the Pro Cheer League required more than creating a compell...
07/05/2026
Full Day Productions and GSE Worldwide have announced Spikes Under the Lights, a...
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
Two multi-role L3Harris products - the Red Wolf launched effects vehicle and SK...
07/05/2026
L3Harris will be developing key features of a secure and resilient digital infra...
07/05/2026
Alysa Liu and Shohei Ohtani Help Drive Viewership as 91 of the Top 100 Broadcast...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
Cobalt Digital Wins Two Future Best of Show Awards at 2026 NAB Show
Manufacturer Recognized by TV Tech and TVBEurope for Innovation in signal processing
Cobal...
07/05/2026
Software and hardware platforms, AI power and user-friendliness on show...
07/05/2026
Intinor will demonstrate its latest technical enhancements for the Direkt series at BroadcastAsia 2026. With a continued focus on reliable contribution and remo...
07/05/2026
Bitmovin has announced that MUBI has chosen Bitmovin as its cloud VOD encoding partner, replacing MUBI's legacy on premises encoding setup to improve scalab...
07/05/2026
Meet Graduates from Berklees Class of 2026 Members of this years graduating class reflect on their proudest moments at Berklee and look ahead to whats next.
...
07/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
07/05/2026
At BroadcastAsia 2026, Interra Systems will demonstrate its latest innovations in automated quality control (QC), real-time monitoring, and captioning. The comp...
07/05/2026
At this year's Broadcast Asia, PlayBox Neo is set to unveil recent innovations across its PlayBox Neo Suite and integrated range of broadcast media solution...
07/05/2026
Strategic three-year partnership marks delivery phase of BFBS' next-generation media vision
Media organisation and military charity BFBS (British Forces Br...
07/05/2026
Amagi, the agentic industry cloud platform for unified broadcast, streaming, and monetization, today announced the availability of its In-Content Ads offering v...
07/05/2026
Lightware Visual Engineering has developed Rack Taurus for rack-based environments such as education and corporate training spaces. It enables clean and simple ...
07/05/2026
Jigsaw24, the UK's leading media equipment supplier and systems integrator, will showcase its expanded end-to-end workflow capabilities at MPTS 2026, signal...
07/05/2026
Ease Live, an Evertz company, today announced that it has been granted a US Patent for its proprietary graphical overlay technology, the foundation for interact...
07/05/2026
Test & measurement innovator Leader Electronics of Europe will present an extensive range of Leader, PHABRIX and LeaderPhabrix test and measurement solutions at...
Applicable Products Part number Description 
