Applicable Products Part number Description
ZETA-NLP-LTE1 (EU) Ultra Low Power European LTE Cat 1 Modem
ZETA-NLP-LTEM (GL) Ultra Low Power Global LTE Cat M Modem
Objective Power consumption is one of the key requirements of any Wireless IoT application.
A significant contributor to power consumption in such systems is the Cellular modem.
This application note shows how to set Siretta ZETA NLP modem in ultra-low power mode for reduced energy consumption.
Solution ZETA-NLP Ultra Low Power Mode The ZETA-NLP has a special mode of operation which forces the unit to drop down to an ultra-low power state where the modem is still operational and registered on the network but is functionally asleep. This allows for the modem to remain connected to the network and be ready to send and receive data using a fraction of the energy.
This ultra-low power state is achieved by setting the following AT command to the modem:
COM3 - Tera Term VT
File Edit Setup Control Window Help
AT CFUN=5
OK
Ultra Low Power Control Signal To control the power state of the modem from low power to ultra-low power it is necessary to use a special control signal in the RS232 serial port.
The control signal is called Data Terminal Ready (DTR) and is available on the RS232 serial port on pin 4 as shown in the table below.
Once the CFUN=5 command has been issued then the modem is ready to enter ultra-low power mode. To activate low power mode and put the modem in to a dormant state the DTR line must be de-asserted on the serial port. When the device has entered ultra-low power mode the CTS line will be de-asserted indicating that the device has gone into ultra-low power state. At this point the serial port is also deactivated, and the modem will not respond to AT commands and will appear to be OFF.
To bring the modem back to normal power state and communicate with the modem again it is necessary to assert the DTR line and the modem will leave its dormant state and become fully active again for normal operation. When in the dormant ultra-low power state an incoming call request or incoming SMS will force the modem to enter its full power mode and the modem is able to be used as normal.
Pin Name Usage Status Direction
1 DCD Output from UART that indicates the carrier 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
This mode allows the modem to consume little current whilst it is not in use but be available for use locally by asserting the DTR line. The modem power ON and power lines will remain active throughout and can also be used to turn the modem completely OFF.
DTR Control Software To control the DTR line on the modem and communicate with the AT command interface on the RS232 serial port it is necessary to use Terminal software which controls the DTR line. Siretta has tested the ZETA modem family with several terminal emulator applications which support DTR and RTS control signalling. Two recommended applications are shown below:
Realterm (Download Link)
Telit AT Controller
Ultra Low Power Receiving Data In the ultra-low power state, a special provision must be catered for when data is received from a connected socket to be output over the serial port.
In this mode it is necessary to run the serial port in the following state:
Enable hardware flow control with AT&K3
Enable low power mode by issuing AT CFUN=5
Setup a socket connection and establish an active connection
Enter ultra-low power state by de-asserting DTR control line
De-assert RTS line
Wait for specified timeout to check for incoming data
When the timeout has expired, to check for data over the connected socket follow the procedure below:
Assert DTR line to disable low power state and activate full serial port
Assert RTS line to receive full buffered data over serial port and wait for all data to be received
When all data has been received de-assert RTS line
De-assert DTR line to re-enter low power state and wait for the specified timeout to receive further data.
NOTE - While there is no data pending reception from the cellular network, the modem does meet the published low power consumption figures. However, if there is data pending from the cellular network, then the modem power consumption rises to approximately 5mA at 12V until the data transfer process has completed and low power state is re-entered. The modem does not automatically enter the full power state when there is pending cellular network data, so the connected application is required to periodically poll the cellular network. If there is pending data from the cellular network, this will immediately start to be received over the serial connection.
Once the data transfer is complete, the modem can be put back into the low power state where it will meet the published power consumption figures. The shorter the check interval, the less time will be potentially spent at the higher 5mA current consumption. The longer the check interval the less power will be used checking for received data from the network. Choose this check interval to match the requirements of your system.
Demonstration of Solution Testing Ultra Low Power Mode using an Outgoing Socket Connection COM3 - Tera Term VT
File Edit Setup Control Window Help
//Set extended error
Europe Stories
05/01/2027
Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...
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...
02/05/2026
Dalet, a leading technology and service provider for media-rich organizations, t...
01/05/2026
January 5 2026, 18:30 (PST) NBCUniversal's Peacock to Be First Streamer to ...
01/04/2026
January 4 2026, 18:00 (PST) DOLBY AND DOUYIN EMPOWER THE NEXT GENERATON OF CREATORS WITH DOLBY VISION
Douyin Users Can Now Create And Share Videos With Stun...
04/03/2026
For many fans, a song's backstory can be just as compelling as the final pro...
04/03/2026
In 2006, Spotify was founded on the belief that technology could bring artists a...
04/03/2026
Spotify is back on the ground for the Houston Livestock Show and Rodeo, and we&#...
04/03/2026
Spotify had an energizing week in Sydney, Australia, filled with powerful conver...
04/03/2026
Earlier this year, we launched Directed By, a documentary-style series that pull...
04/03/2026
KT and Rohde & Schwarz to showcase AI-enhanced radio transmission performance In a joint 6G AI proof-of-concept demonstration, the CMX500 one-box tester from ...
04/03/2026
Luxembourg, 3 March 2026 - SES S.A. has today published its 2025 Annual Report, following the announcement of the company's full year financial results for ...
04/03/2026
Luxembourg, March 3, 2026 - SES, a leading space solutions company, along with I...
04/03/2026
04 Mar 2026
VEON Partners with GSMA Innovation Fund to Accelerate Digital Innov...
04/03/2026
04 Mar 2026
VEON's Beeline Uzbekistan and Rakuten Symphony Partner for Open...
04/03/2026
Wednesday 4 March 2026
Sky Sports unveils plans for 2026 Formula 1 coverage
Sky Sports is preparing for one of the most highly anticipated F1 seasons in recen...
03/03/2026
For many, finding time or headspace to pick up a book can feel out of reach, but...
03/03/2026
Rohde & Schwarz and Realtek demonstrate first test solution for Bluetooth LE Hi...
03/03/2026
eds3_5_jq(document).ready(function($) { $(#eds_sliderM519).chameleonSlider_2_1({ content_source:......
03/03/2026
Luxembourg, 2 March 2026 -- SES S.A. fully consolidates Intelsat from 17 July 2025 and announces financial results for the year ended 31 December 2025
FY25 Pe...
03/03/2026
RT is proud to support a rich and diverse programme of arts and cultural events taking place across Ireland throughout March 2026. This month brings a remarkab...
03/03/2026
03 Mar 2026
VEON and MeetKai Expand Collaboration to Explore Sovereign AI Infra...
03/03/2026
Tuesday 3 March 2026
Sky releases official trailer for The Miniature Wife, a Sk...
03/03/2026
Tuesday 3 March 2026
Ryan Reynolds and Rob Mac land first ever live commentary ...
03/03/2026
Tuesday 3 March 2026
The Dyers' Caravan Park reopens for a second season after a hit launch on Sky
The Dyers' Caravan Park
JPEG (510KB)
Sky books a ...
03/03/2026
Harmonic's cOS Virtualized Broadband Platform Simplifies Network Operations, Lowers Hardware Dependency and Enables Seamless DOCSIS and Fiber Growth SAN JO...
03/03/2026
Comscore to Announce Fourth Quarter and Full Year 2025 Financial ResultsRESTON, VA, March 3, 2026 Comscore, Inc. (Nasdaq: SCOR), a trusted partner for plannin...
03/03/2026
Self-taught on iMovie, Hanagami transitioned to Final Cut Pro in 2009, discovering that professional tools could give him full creative control over how his wor...
03/03/2026
RT Media Sales has announced Spry Finance has renewed it's sponsorship of M...
02/03/2026
Rohde & Schwarz demonstrates FR1-FR3 carrier aggregation, advancing 6G readiness Rohde & Schwarz and Qualcomm Technologies, Inc. have reached another pivotal ...
02/03/2026
aconnic AG (ISIN: DE000A0LBKW6), Munich, and Arqit Quantum Inc. (Nasdaq: ARQQ, A...
02/03/2026
Luxembourg, February 26, 2026 - SES and Africa Mobile Network (AMN) have expande...
02/03/2026
Monday 2 March 2026
Saturday Night Live UK announces writing team
L-R: Jonno Johnson; Charlie Skelton; Celya AB; Omar Badawy; Gr inne Maguire; Laura Claxton; ...
27/02/2026
Since its inception, Gorillaz has been known for blending art with genre-bending...
27/02/2026
This week, Spotify introduced Audiobook Charts for the U.S. and U.K. The charts make it easy to discover your next favorite book by showing what's popular a...
27/02/2026
Rohde & Schwarz and Viasat to collaborate on NB-NTN IoT test plan for connectivi...
27/02/2026
In media technology, big features often steal the spotlight - AI integrations, cloud transformations, automation frameworks. But for the people who use these to...
27/02/2026
Digital Asset Management systems sit at the heart of most marcoms operations. They centralise content, organise it, and make it discoverable. Integrated with th...
27/02/2026
The AI Wild West comes to NAB 2026 and Blue Lucy is bringing the Sheriff
The AI Wild West is here, and media organisations are feeling the heat. On Booth W23...
27/02/2026
A deeply personal, uncompromising portrait of the legendary punk rock iconFriday...
27/02/2026
One of Ireland's favourite lifestyle shows Home of the Year, returns for its 12th series and will be proudly sponsored by SIRO. The brand-new series will ai...
27/02/2026
Our Farm: A GIY Story lands on RT One and RT Player from March 3
From walled garden to community farm, new six-part series captures the unfiltered realities...
27/02/2026
Note: English version included below the Irish language version.
Seachtain na Gaeilge 2026 ar RT
A Ghaeilge mo cheol th '
T feachtas athnuaite i n...
26/02/2026
Rohde & Schwarz awarded contract by Israel Airports Authority for QPS201 securit...
26/02/2026
Rohde & Schwarz highlights its unique CMX500 one-box tester tailored for NTN tes...
26/02/2026
Rohde & Schwarz high-efficiency transmitter powers next-gen broadcast services i...
26/02/2026
Rohde & Schwarz highlights its comprehensive embedded systems test solutions at ...
26/02/2026
Rohde & Schwarz to showcase spectrum security and network efficiency solutions a...
Applicable Products Part number Description 
