Introduction
VoLTE uses 4G (LTE) technology to transfer voice audio from one point to another using digital packets as opposed to 3G (UMTS) and 2G (GSM) networks which transfer voice audio over a dedicated analogue channel. VoLTE has many advantages which includes, less bandwidth to transfer higher quality audio than voice calls made by 3G (UMTS) and 2G (GSM) technologies. VoLTE has very much more data carrying capacity compared to 3G (UMTS) and 2G (GSM) technologies and as such can connect many more calls simultaneously.
Below are the lists of Siretta Modems that support VoLTE:
ZETA-NLP-LTE1 Ultra Low Power LTE Cat 1 (EU) Siretta Enabling Industrial IoT
ZETA-NSP-LTE1 Low Power LTE Cat 1 (EU) Siretta Enabling Industrial IoT
ZETA-NEP-LTE4 (EU) with RS232, USB serial and GPIO Low Power LTE Cat 4 European Modem with GPIO Siretta Enabling Industrial IoT
ZETA-GEP-LTE4 (EU) with RS232, USB serial, GPIO and GNSS Low Power LTE Cat 4 European Modem with GPIO and GNSS Siretta Enabling Industrial IoT
This application note guides users on how to transfer voice audio over LTE technology from a Siretta modem using the ZETA-NLP-LTE1 (EU). The VoLTE solution is simple to implement, where users make a voice call from a Siretta Modem to a Mobile phone or Land line number. Once a call is answered, voice audio, music audio or DTMF tones can be sent from the PC attached to the Siretta Modem via the USB interface to the Mobile/Landline that answers the call.
A good use case for VoLTE is in a data call centre which allows call forwarding and call waiting rules. In addition with specific mobile partner software running on the PC, the Siretta modem can be used to make voice calls in a similar way to a mobile phone device.
Equipment used for this application note:
Siretta Part Number: 61054 (ZETA-NLP-LTE1 (EU) Starter Kit (A Low Power Modem with RS232 and USB serial) Ultra Low Power LTE Cat 1 (EU)
Modem Starter Kit- Quick Start Guide ZETA-xxP Quick Start Guide
Initial Modem Setup Guide Application Note Initial Modem Setup Guide Application Note
IMS enabled SIM card with the ability to make and receive voice calls.
Mobile phone for making and receiving voice calls.
A PC with an installed Terminal Emulator program (Window 10 Laptop installed with Tera Term is used for this guide)
AT command reference manual for ZETA-NLP-LTE1 (EU) ZETA-xxP-LTE1 / ZETA-xxP-LTE4 AT Command Reference Manual
Steps:
1. Follow the Modem Starter Kit-Quick Start Guide.
2. Follow pages 1 to 5 of the Initial Modem Setup Guide Application Note.
NOTE: Make sure you use a 4G / LTE enabled SIM card that supports VoLTE (IMS) with the ZETA-NLP-LTE1 (EU).
3. Set Modem to 4G (LTE) by issuing the following AT command AT WS46=28
4. You will receive OK when modem is set to 4G (LTE) technology.
5. Check if Modem is registered to a network by issuing AT CREG?
NOTE: Modem is registered to a local network (if it returns CREG: 0,5 means it is registered to a roaming network. If you have problems with this stage please contact support.)
6. Leave default value for AT#DIALMODE=0 (Setting for voice call only).
7. Set service class as voice by issuing AT FCLASS=8
8. You will receive OK when service class is set to voice.
9. Check if device is registered with IMS using the following command AT CIREG?
NOTE: IMS is required for VoLTE and is also known as the IP Multimedia Subsystem.
10. Receive CIREG: 0,1 when it is registered to IMS, if not check if IMS service is enabled or not by issuing the following AT command AT#IMSPDPSET?
11. Also, the user can check IMS using the following AT command AT CGDCONT?
NOTE: For the ZETA-NLP-LTE1 (EU) modem the IMS service uses profile 2 as seen above.
12. Use the following AT command AT$QCPDPIMSCFGE? To confirm profile 2 is enabled.
13. The settings for ZETA-NLP-LTE1 (EU) to make a voice call is now complete.
14. Dial a voice call from ZETA-NLP-LTE1 (EU) to a mobile number 07400245346 by issuing ATD07400245346;
15. You will receive OK.
16. Mobile phone will start to ring, indicating an incoming call from the ZETA-NLP-LTE1 (EU).
17. Answer incoming call from ZETA-NLP-LTE1 (EU).
18. A voice call is established between the ZETA-NLP-LTE1 (EU) modem and the mobile phone.
19. Once a voice call is established then issue the following AT command AT VTS=123456789 from the modem, ZETA-NLP-LTE1 (EU).
20. You will hear DTMF tones from the mobile phone speaker corresponding to 123456789.
21. You have successfully made a voice call and transferred DTMF tones over LTE.
NOTE: This DTMF feature can be used to automate responses to a third party system.
Application Example:
The example below shows how the ZETA-NLP-LTE1 (EU) modem can be integrated with the standard PC application Audacity. Audacity is a free and open-source digital audio editor and recording application which can be downloaded from the following link Download | Audacity (audacityteam.org).
22. Download Audacity, depending on your operating system (Supported Window 7-10, macOS and Linux).
23. For this guide Audacity for Windows 7-10 is installed on a Windows 10 PC.
24. Connect the ZETA-NLP-LTE1 (EU) modem to a PC using a USB-A to USB-B cable.
25. Go to the PC device manager and check that the Telit USB appears under the Modems listing.
NOTE: If the Telit Modem did not appear on the device manager then download the USB drivers from Software Library Siretta Enabling Industrial IoT Software Updates or contact your Siretta representative.
26. Once the modem is connected, issue the following AT command to the Modem AT#USBCFG=11 (To enable voice over USB).
27. Receive OK when the command is accepted.
28. The modem will instantly reboot.
29. The Terminal (Tera Term) will disconnect from the COM port until reboot cycle is completed and connection is re-established.
30. Issue the following
Most recent headlines
06/10/2025
France T l visions, France's leading broadcaster, has received the 2025 EBU ...
04/09/2025
Monumental Sports & Entertainment (MSE), in collaboration with Dalet, has been a...
30/08/2025
WASHINGTON The Federal Communications Commission has adopted its FY 2025 Regulatory Fees Order that establishes the regulatory fee rates for the broadcast stati...
29/08/2025
Australian Red Cross and SBS launch training to help workplaces in the fight aga...
29/08/2025
The National Film and Video Foundation (NFVF), an agency of the Department of Sp...
29/08/2025
L3Harris Technologies has concentrated decades of expertise across the entire enterprise to develop affordable and reliable best-of-breed solutions to rapidly c...
29/08/2025
BURBANK, Calif. The CW Network and the Pac-12 Conference have announced a new media rights deal that will extend their broadcast partnership beginning with the ...
29/08/2025
NEW YORK Gracenote has released a new analysis of its global video dataset showing that the number of FAST channels grew nearly 14% from Q1 2025 and 76% since 2...
29/08/2025
SAN JOSE, Calif. Harmonic has announced a series of improvements to its live sports streaming solution that the company said will improve fan engagement, protec...
29/08/2025
NEW YORK and LOS ANGELES Fox Corp. and YouTube TV last night announced a renewal of the full portfolio of Fox networks, including Fox News Channel, Fox Business...
29/08/2025
Budapest, Hungary, August 2025 - The integration of Microsoft Teams Rooms (MTR) with Lightware's Taurus universal matrix switchers delivers a new level of f...
29/08/2025
Frequency, the engine behind many of the world's best-known streaming television channels, today announced it will launch Studio Live, a next-generation uni...
29/08/2025
In an era when AI and cyber resilience are essential, Scality will mark the 10th anniversary of Scality Day on October 16, 2025 in Paris. This flagship global e...
29/08/2025
Disguise's In-House Creative and Technical Teams Pre-Visualised, Programmed and Delivered Content for the Experience, All Powered by EX 3+
Technology solu...
29/08/2025
Disguise will be demonstrating the latest workflows for TV, film and live events on a number of partner booths at the show
Disguise, the industry-leading tech...
29/08/2025
STOCKHOLM, Sweden Accedo will showcase Accedo Compose, its AI agent-powered modular orchestration layer that assists streaming providers in transitioning client...
29/08/2025
LOS ANGELES Cineverse has announced that it is working with Xperi to bring four of its streaming channels to automobiles for the first time as part of the DTS A...
29/08/2025
DALLAS & ATLANTA Gray Media has announced an agreement with the sports streaming service Victory+ to simulcast 17 Dallas Stars NHL games in 15 television market...
29/08/2025
NEW YORK AND CULVER CITY Comcast NBCUniversal and Amazon have announced new and extended distribution agreements that will expand the content available on their...
29/08/2025
FOOTHILL RANCH, Calif. RED Digital Cinema will feature its Cine-Broadcast Module supporting live broadcast workflows during IBC2025, Sept. 12-15, at the RAI Ams...
29/08/2025
29 Aug 2025
Kyivstar Rings Opening Bell at Nasdaq Marking Landmark Listing and ...
29/08/2025
More than half of all NFL games live on Sky for the first timeFriday 29 August 2025
Sky Sports has announced a new three-year deal with the NFL, extending its ...
29/08/2025
Back to All News
RIV4LRIES: The Trailer of the New Series With Samuele Carrino ...
29/08/2025
Get ready for an inspiring and emotional insight into the world of competitive Irish dancing with My Story: Tomi Champion of the World airing on RT 2 this monda...
29/08/2025
RT has today announced that David McCullagh is to be the new presenter of RT Radio 1's flagship Today programme, which airs every weekday at 10am, replaci...
28/08/2025
By Kristin Feeley, Director, Documentary Film & Artist Programs
If you want to tell untold stories, if you want to give voice to the voiceless, you've got ...
28/08/2025
Directed by Steven Bognar and Julia Reichert, Sundance Institute-supported Amer...
28/08/2025
Corridos have been a cornerstone of M sica Mexicana for generations, telling stories rooted in everyday life. Now, a new chapter is taking shape: motivational c...
28/08/2025
Los corridos han sido un pilar de la M sica Mexicana durante generaciones, contando historias enraizadas en la vida cotidiana. Ahora, un nuevo cap tulo est tom...
28/08/2025
Earlier this month, we promised our Verano Forever party would bring the heat, a...
28/08/2025
L3Harris will provide the Polish F-16V fleet with the Viper Shield electronic warfare system as part of an upgrade program....
28/08/2025
Bilbao, August 26, 2025 - AgileTV, an international television and video technol...
28/08/2025
Ken Wilkinson is an Emmy Awards nominated New York audio engineer who specialises in production sound mixing for film, commercial, episodic and documentary work...
28/08/2025
NEW YORK FuboTV today announced that it will launch Fubo Sports, a skinny bundle that focuses on sports with a subscription price of $56 monthly....
28/08/2025
NEVADA City, Calif. At IBC2025, Sept. 12-15 at the RAI Amsterdam, Telestream will debut its new Global Ingest strategy, introducing a next-generation ingest arc...
28/08/2025
Dr. Rhoda Bernard Releases Groundbreaking Debut Book on Accessible Arts Educatio...
28/08/2025
TAG Video Systems, the leader in software-based IP end-to-end workflow monitoring, deep probing, and real-time visualization, has named Oliver Gappa as Sales Di...
28/08/2025
AI-based voice enhancement will be among a series of innovations making their IBC 2025 debut on the DHD stand B46 in Hall 8 at the RAI Amsterdam Convention Cent...
28/08/2025
Telef nica Servicios Audiovisuales (TSA), the leading system integrator and service provider in the media sector in Spain, with the support of Appear, the globa...
28/08/2025
To fully immerse sailing fans in the world's biggest offshore yacht race, production company, Optical Media turned to LiveU's On-site Production solutio...
28/08/2025
Working with Calrec on its most recent overhaul, radio and television broadcaster, WNED has migrated to a fully IP infrastructure with multiple Type R consoles,...
28/08/2025
Cleeng, the Subscriber Retention Management (SRM ) inventor, has unveiled Cleeng Pro, the first-ever direct-to-consumer (D2C) subscription management platform t...
28/08/2025
Zixi, the industry leader in live broadcast-quality video over IP, today announced that French media distribution platform OKAST has selected Zixi to enable rel...
28/08/2025
Solution offers a streamlined, speaker-free architecture to optimize integration with premium external loudspeakers and advanced loudness metering
Nixer Pro Au...
28/08/2025
Cinegy, the premier provider of software-defined television technology, has announced a strategic partnership with Vision One Touch Film Production Services L.L...
28/08/2025
Telestream, a global leader in media workflow technologies, will debut its new Global Ingest strategy at IBC2025, introducing a next-generation ingest architect...
28/08/2025
Tier 1 operator selects Broadpeak to power high-performance, unified CDN solution across Norway, Sweden and Finland
Broadpeak, a leader in streaming and moneti...
28/08/2025
Leading video software provider, Synamedia, today announced that 24 Frames Digital, one of India's leading live event streaming service providers, has chose...
28/08/2025
Meet VisualOn at IBC2025: See What's Next in AI-Powered Video Streaming Join VisualOn at IBC2025 and discover how our AI-driven Optimizer and advanced media...
Introduction 
