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 ...
14/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
14/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
14/11/2026
Newest Lenses, Horizon Anamorphic Seminar & Guided Lens Character Experience Highlight Creative Possibilities
At the 2026 Toru CAMERIMAGE Film Festival, ZEISS...
14/11/2026
Sonnet Announces Black Friday Sale on Select Products
Brie Clayton November 14, 2026
0 Comments
WHAT: Sonnet Technologies is having a sale on a select...
14/11/2026
Berklee Alumni Shine at the 2026 Latin Grammy Awards This year's winners included songwriters, engineers, and performers who contributed to acclaimed reco...
13/11/2026
The UIM E1 Series wraps its third season this week with the Bombay Sapphire E1 Miami GP, Nov. 11-14, on Biscayne Bay at the Miami Seaplane Base on Watson Island...
13/11/2026
In-venue and creative video staffers at the professional and collegiate level ha...
13/11/2026
Singer-songwriter Benson Boone will headline entertainment for the Discover NHL Winter Classic between the Utah Mammoth and Colorado Avalanche at Rice-Eccles St...
13/11/2026
Blackmagic Design has announced the Blackmagic Ambisonic Microphone, a 7th order ambisonic microphone array that captures spatial audio for immersive video prod...
13/11/2026
SMPTE has announced that The Studio B&H and Riedel Communications will provide the video infrastructure and communications technology for the Solutions Hub at t...
13/11/2026
The Hollywood Professional Association (HPA) has announced the theme and program focus for the 2027 HPA Tech Retreat, which takes place Feb. 14-18, 2027, in La ...
13/11/2026
Football Manager 27 Touch is available on Apple Arcade starting today. The game ...
13/11/2026
MotoGP has announced a two-year media rights agreement with ESPN covering the Un...
13/11/2026
Apple Sports, the free iPhone app, has added the Ultimate Fighting Championship (UFC) to its lineup of supported sports, in time for Saturday's UFC 334. The...
13/11/2026
The NBA and Fanatics Studios, the joint venture between Fanatics and entertainme...
13/11/2026
ESPN held its annual EDGE Innovation Conference last night and offered up an ove...
13/11/2026
Regional sports network gives Ithaca College, SUNY Cortland students a platform to thrive
One of the biggest games in Division III college football will be pla...
13/11/2026
Studer-inspired 500-series PWM compressor unveiled
The HLabs range already includes a couple of Studer-inspired offerings in the form of the PRE169 and EQ16...
13/11/2026
Download Now!
To view the white paper, please enter the following details:
--
First Name* First Name
Company*
Country* Please select your countryA...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Blue Lucy, the workflow orchestration and integration platform for broadcasters, rights owners and localisation companies, today announced an integration with c...
13/11/2026
Krotos announces Black Friday offers on Studio Pro and Studio Max
Brie Clayton November 12, 2026
0 Comments
First-year annual plans start at US$195.99...
13/11/2026
Blackmagic Design Announces Blackmagic Ambisonic Microphone
Brie Clayton November 12, 2026
0 Comments
New 7th order ambisonic microphone with 108 MEMS...
13/11/2026
Meet the Berklee Student Setting Planetary Motion to Music With his compositional platform SoniKosmos, Javier Roqueni aims to make the universe the ultimate i...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , er...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , er...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Share
{alert(Link copied)}).catch(err => {console.error(Failed to copy: , err)}) data-platform=copy_link data-action= class=font-ui-heading py-2 text-sm tex...
13/11/2026
Amagi, the media industry cloud company, today announced a partnership with Golden Times Media Technology (stock code 920021.BJ), a Beijing-based media and tech...
13/11/2026
CGI (TSX: GIB.A) (NYSE: GIB), one of the largest independent IT and business consulting services firms in the world, together with its Malaysian partner, Cedar ...
13/11/2026
SMPTE, the home for media professionals, technologists and engineers, today announced that The Studio B&H and Riedel Communications will provide the video infra...
13/11/2026
iWedia, a global leader in connected TV software solutions, will present its software-first approach to DRAM optimization at Android TV APAC Summit 2026 in Bang...
13/11/2026
Beginning today, November 13, Apple HomeView is available for purchase at Apple Store locations, on the Apple Store online, and in the Apple Store app in select...
13/11/2026
From pediatric research to smart hospitals, AI is helping care teams spend less time on routine tasks and more time with patients.
Health systems and startups...
12/11/2026
Industry leaders examine how Dynamic Media Facility, Media eXchange Layer, and c...
12/11/2026
The junior Tar Heel is embracing the technical and creative challenges of live production while emerging as a leader and mentor in the control room...
12/11/2026
Gracenote, Nielsen's content intelligence business, has released its fifth a...
12/11/2026
RTL Deutschland will bring the NHL to free-to-air TV in Germany starting Nov. 30...
12/11/2026
Clear-Com supported On Air 2026, a 24-hour student-led broadcast connecting 45 u...
12/11/2026
uniqFEED has opened a Remote Operations Center (ROC) in Madrid, Spain. It is already operational, delivering virtual advertising for LaLiga matches. The ROC is ...
Applicable Products Part number Description 
