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 ...
06/09/2026
June 9 2026, 23:00 (PDT) Dolby and MagentaTV Bring Fans Closer to the FIFA Worl...
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...
15/06/2026
Detach from Direct-Attached: How Remote Editing with EVO Keeps Creative Teams Mo...
14/06/2026
Library captures 1960s R&B/pop drum sound
Following on from their recent wave of plug-in effects, Iconic Instruments have just launched an all-new virtual d...
14/06/2026
HBO Comedy Rooster Shot with URSA Cine 17K 65
Brie Clayton June 14, 2026
0 Comments
Large format brings viewers intimately close to characters.
Black...
13/06/2026
Latest expansion pack includes 252 presets
Devious Machines have recently introduced another expansion for their powerful multi-effects plug-in, Infiltrator...
13/06/2026
Create custom DAW/plug-in controllers using prompts
MetaGrid have recently introduced an all-new AI Builder function to their touchscreen-based control surf...
13/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
13/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
YES Network and The Gotham Sports App will air seven Athletes Unlimited Softball...
12/06/2026
The United Football League will host its FAST Innovation Suite at the 2026 United Bowl presented by Credit One Bank on Saturday, June 13 at 3:00 p.m. ET at Audi...
12/06/2026
PTZOptics and LayerJot will present live demonstrations at InfoComm 2026 showing how natural-language AI prompting, robotic camera control, and on-device comput...
12/06/2026
MultiDyne Video and Fiber Optic Systems will exhibit at InfoComm 2026, featuring...
12/06/2026
Ateme has announced that Eurovision Services is using Ateme's software-based frame-rate conversion technology for international live event workflows. The de...
12/06/2026
Bitmovin and Simplestream have announced a partnership with Xperi to simplify the launch of OTT streaming services on TiVo OS smart TVs and devices. The collabo...
12/06/2026
Net Insight has announced that a multinational technology company is deploying a...
12/06/2026
MLB Players Inc., the business arm of the MLB Players Association, has announced a partnership with Athletes First to develop and sell brand partnerships across...
12/06/2026
Guntermann and Drunck (G&D) and VuWall have announced the CommandKeyboard-Advanc...
12/06/2026
Comcast Smart Solutions announces a new smart technology deployment with Major L...
12/06/2026
Elevation Worship completed the initial leg of its Elevation Nights 2026 tour ...
12/06/2026
AJA Video Systems has announced KONA IP25 support for Colorfront Transkoder and ...
12/06/2026
Audinate Group Limited (ASX: AD8) will exhibit at InfoComm 2026 (Booth C7321, Ce...
12/06/2026
Pac-12 Commissioner Teresa Gould has announced the appointment of Scott Adametz as Chief Technology Officer. The Pac-12 describes the hire as the first CTO appo...
12/06/2026
Grass Valley has announced AMPP Edge Live, a production system combining Grass Valley hardware, NVIDIA Blackwell GPU acceleration, and AMPP OS in a single platf...
12/06/2026
At one time a trailblazer with the launch of the Longhorn Network, the Universit...
12/06/2026
Ratings Roundup is a rundown of recent rating news and is derived from press rel...
12/06/2026
Chyron has announced PAINT 10.4, an update to its illustrated replay and sports ...
12/06/2026
SVP, Production, Mark Gross: With the new schedule, with not having every Sunday night, it has given us an opportunity to take a step back and reimagine what o...
12/06/2026
For Televisa Technical Engineering Manager Roberto N nez Ibarra and the small team of 12 technicians and two production personnel at the IBC things are already ...
12/06/2026
Simple Steps to Better Acoustics - Taming The Small Room
Most of us mix in spare rooms and small spaces, where the acoustics fight us at every turn. At Gear...
12/06/2026
Latest addition expands vintage-inspired effects palette
Meris' Ottobit pedal range draws its inspiration from vintage gaming consoles, and the latest a...
12/06/2026
Soundbox-based chamber strings series expanded
Sonora Cinematic have just announced the launch of the second instalment in their Soundbox-based chamber stri...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
AJA Announces KONA IP25 Integration with Colorfront Software
Brie Clayton June 12, 2026
0 Comments
Collaboration enables uncompressed SMPTE ST 2110 I/O ...
12/06/2026
URSA Cine 12K LF Used to Create Visuals for STUTS' K-Arena Concert
Brie Clayton June 12, 2026
0 Comments
Organic visuals projected on a giant scre...
12/06/2026
MTI FILM Acquires Mango New Edit, Expanding its Global Post-Production Services ...
12/06/2026
AI Point Tracking Speeds Up Complex VFX Tracks in Mocha Pro
Jessie Electa Petrov June 12, 2026
0 Comments
The 2026.5 release adds automatic point trac...
12/06/2026
Bitmovin, a provider of video streaming solutions, has partnered with Simplestream, a provider of OTT and broadcast solutions, and technology provider Xperi, to...
12/06/2026
Leostream Corporation, creator of the world-leading Leostream Remote Desktop Access Platform, today announced Jigsaw24, a leading B2B IT solutions provider wit...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
12/06/2026
How Aussie indie games and screen are levelling up with IP 11 June 2026
Ari Harrison, Pro Jank Footy
Head of Games Joey Egger and Ari Harrison of Umbrella sha...
12/06/2026
AgentPerf from Artificial Analysis, the industry's first agentic AI benchmark, gives developers, enterprises and infrastructure providers a clear way to com...
Applicable Products Part number Description 
