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...
13/05/2026
New Adobe Premiere Color Grading Mode Accelerated on NVIDIA GPUs
Joel Pennington May 13, 2026
0 Comments
New NVIDIA RTX-accelerated features streamlin...
13/05/2026
Grass Valley announced that dB Broadcast has delivered new IP-based outside broadcast (OB) trucks for Cloudbass, featuring Grass Valley LDX 100 Series cameras a...
13/05/2026
Ikegami will exhibit the latest additions to its wide range of broadcast production cameras, control units, viewfinders and monitors on stand 5D3-1 at Broadcast...
13/05/2026
FISE, working with the founding members of the XR Sports Alliance (XRSA), Accedo, Qualcomm Technologies, Inc. and HBS, have collaborated to develop an immersive...
13/05/2026
Canon Unveils New EOS R6 V Full-Frame EOS Camera and RF20-50mm F4 L IS USM PZ Bu...
13/05/2026
Boston Conservatory at Berklee Honors Beth Morrison and Moses Pendleton at Comme...
13/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/05/2026
Creative software developer Foundry today announced the latest developments on Nuke Stage. A purpose-built application for end-to-end virtual production and in-...
13/05/2026
A definitive portrait of one of Ireland's most influential musicians
New TV documentary airs Monday 18 May on RT One and RT Player at 9.35pm
Watch the...
13/05/2026
Agentic AI is changing the way users get work done. Following the success of OpenClaw, the community is embracing new open source agentic frameworks. The latest...
13/05/2026
Reinforcement-learning agents - AI systems that learn by trial and error - can c...
12/05/2026
Beyond the Hype: A Strategic Post-Hoc Analysis of NAB 2026 If NAB Show 2026 had an underlying theme, it was a quiet, industry-wide pivot from the high-energy sp...
12/05/2026
Guntermann and Drunck (G&D), a Panoptec Technologies Group company, and CT Square, led by Chandresh Shah, have announced a joint venture to distribute G&D and V...
12/05/2026
With 30 days until the start of the FIFA World Cup 2026, Telemundo, the exclusive Spanish-language home of the tournament in the United States, has announced th...
12/05/2026
The NHL has announced the return of Stanley Pup for its third consecutive year, a 90-minute special featuring adoptable rescue dogs competing on a miniature rin...
12/05/2026
NBCUniversal presented its 2026 Upfront to advertisers at Radio City Music Hall, detailing upcoming programming across NBC, Peacock, Bravo, and Versant properti...
12/05/2026
FOX Sports has announced funding for the Fandom and Social Connection Initiative at Harvard Kennedy School's Shorenstein Center on Media, Politics, and Publ...
12/05/2026
TNDV and Live Media, both divisions of Live Media Group, supported live broadcast coverage around NCAA Final Four weekend in Indianapolis, including the March M...
12/05/2026
The European Football Alliance (EFA) has announced a content distribution agreement with Fubo Sports Network, the free ad-supported streaming TV (FAST) channel ...
12/05/2026
For the first time, Spanish-speaking fans in the U.S. will have two separate tel...
12/05/2026
CP Communications led a comprehensive spectrum management initiative on behalf of Churchill Downs during Kentucky Derby week, coordinating RF assets across the ...
12/05/2026
LiveU has announced a strategic partnership with DRONERESPONDERS, a 501(c)3 non-...
12/05/2026
Open Broadcast Systems has announced that BMC TV, a specialist in IP transport of broadcast content, has selected the Open Broadcast Systems 5G Flyaway solution...
12/05/2026
NEP Europe, part of NEP Group, has announced it will deliver broadcast solutions...
12/05/2026
Grass Valley has announced continued collaboration with Ravensbourne University ...
12/05/2026
Stats Perform has announced the launch of Opta Pulse, an AI-assisted video creation and distribution platform for leagues, rights holders, and broadcasters. The...
12/05/2026
FOX Sports has announced a collaboration with Sesame Workshop to integrate Sesame Street characters into FOX Sports' FIFA World Cup 2026 programming. Conten...
12/05/2026
To date, NHL Productions has produced 19 broadcasts with commentary in American Sign Language
NHL in ASL (American Sign Language) may be just one show, but the...
12/05/2026
Google's Brian Albert: creators, athletes, highlights, nostalgia, second-scr...
12/05/2026
A still from Past Lives by Celine Song, an official selection of the Premieres program at the 2023 Sundance Film Festival. (Courtesy of Sundance Institute | p...
12/05/2026
Spotify is where fans and artists come together, turning discovery into somethin...
12/05/2026
Features patented Marco-MMC clocking technology
Black Lion Audio's latest release combines the company's expertise in clocking with their renowned p...
12/05/2026
New Track Panel, sequencer upgrades & more
Following their recent public beta release, Reason Studios have announced the full release of Reason 14. With the...
12/05/2026
One month to go! SBS reveals expansive FIFA World Cup 2026 lineup beyond the pi...
12/05/2026
Rohde & Schwarz presents its advanced solutions for power electronics testing at...
12/05/2026
aconnic AG (ISIN: DE000A0LBKW6), Munich, has developed a modified fund raising p...
12/05/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/05/2026
Tyrell Corporation, specialists in high-end live sports and entertainment broadcasts, was tasked with delivering compelling broadcast coverage of premier equest...
12/05/2026
Registration is now open for IBC2026 as the global media, entertainment and technology community prepares to converge on the RAI Amsterdam from 11 14 September ...
12/05/2026
Ross Video, a global leader in live video production technology, will present its latest innovations and integrated production workflows at BroadcastAsia 2026, ...
12/05/2026
500 selected leaders from around the world across start-ups, corporates, and venture capital. Over 50bn in assets under management among attending investors, a...
Applicable Products Part number Description 
