LooUQ CircuitRiver

LooUQ CircuitRiver IoT devices provide advanced communications technologies and easy integration to your project.  The LTEm1 modem is an LTE CAT-M1, NB-IOT and EGPRS cellular modem, designed to be embedded in IoT enabled products. The modem is carrier certified with Verizon[1], registered with T-Mobile and incorporates a FCC certified cellular module. With these certifications in place, your product does not require separate network carrier certification[2].  By embedding the modem in your product, you can accelerate the development process for your product and get it to market in less time with reduced risk and cost.

This guide covers the topics your will want to be familiar with in order to use the modem effectively in your project.

Getting Familiar with the CircuitRiver LTEm1 Modem

The LooUQ CR-LTEM1 modem is an advanced LTE M2M (machine-to-machine) embedded cellular modem designed to address the unique requirements of IoT applications.  In addition to the cellular communications capabilities the LTEm1 also has integrated multi-constellation GNSS (aka GPS in US) receiver for mobile applications benefiting from precise location tracking. The GNSS feature only requires the addition of an external antenna.

The LTEm1 modem is a complete embedded communications subsystem. Beyond simple data transmission, the LTEm1 supports numerous protocols found in M2M\embedded projects. By selecting this advanced device, your project is ready to securely and reliably send and receive IoT data streams.  As you will see later in this document LooUQ has abstracted all of the details and intricacies of processing AT commands, allowing you to focus on the functionality that makes your application unique. 

Protocols Supported

  • PING\DNS Lookup
  • HTTP(S)
  • FTP(S)
  • MQTT
  • Other protocols are found on the BG96 but not implemented in the LTEm1c software are PPP and NITZ 

Power Requirements

Typical Power Consumption

Quiet30 mA
Transmitting125 - 155 mA
Special Events< 225 mA
PSM8 - 10 µA

The LTEm1 is designed to be powered by a 3.7-volt LiPo battery pack (typical 3.6v to 4.2v limits).  The typical power profile for LTE Cat-M1 operation is described below in the Specifications | Power section.  LooUQ UXplor adapters are designed to meet the power requirements of the LTEm1.  For more details on the charger\battery pairing see the user guide for the specific UXplor adapter board you are using in your project.

Input VoltageAcceptable input voltage range3.5V to 4.3V
Input Peak CurrentPeak supply current during transmission slot2A
Off StatePowered down leakage current8µA
PSMPower Saving Mode13µA
Sleep StateDRX=1.28s @Real LTE Cat M1 Network10mA
Standby StateDRX=1.28s @Real LTE Cat M1 Network26mA
Active State23dBm

Data Transfer @ Typical Real Network


Important Battery Safety
  • Care should be taken to protect the battery pack from physical damage, overheating, or short-circuit. Protect the battery from physical risks in your design.
  • Battery charging circuits must be designed for 3.7-volt LiPo battery packages.  Never use a battery charger designed for NiCad or other type of battery powering the CTA.
  • The charger circuits on all LooUQ host adapters (HA boards) are designed for LiPo batteries and meet the battery safety and power requirements for all of the LooUQ CTA boards. 

Host Connectivity

LooUQ offers several UXplor development adapters to make connectivity between the modem and your project’s “host processor” quick and seamless.  The LooUQ CircuitRiver devices implement the CR-HostInterface1, which is described in the table below. The physical connection is implemented using a right-angled header along with the 2 snap-fit pins to secure the modem to the host adapter.   The header on the LTEm1 is a 16-pin, 2-row, right-angled header with a pin-pitch of 2.00mm (0.079").  The LTEm1 host header mates with Harwin Part#: M22-2040805 and Adam Tech Part# 2PH2R-16-UA.

UXplor Development Boards

Three development boards are available for the LTEm1(left to right): The UXplor-RPi, UXplor-Feather, UXplor-Breakout.

UXplor-RPi - Is a Raspberry PI Hat-like adapter that provides power to the LTEm1 from the host Pi (the UXplor does not supply the identification ROM for full Hat functionality). There is serial connectivity via the SPI interface, but the LTEm1c device driver is a pure-C99 basic driver and does not provide the full suite of services to be a Raspberry Pi OS (formerly know as Raspbian) kernel level driver. 

UXplor-Feather - The UXplor-Feather is a full featured development\evaluation adapter. It has connections for a Feather format Arduino board (compatible with Adafruit, SparkFun and others), the LTEm1 and a area for prototyping. GPIO, SPI, and I2C access is available in the prototyping area with 2 breadboard pads per signal. There is also a SparkFun Qwiic compatible connector (Adafruit STEMMA) to make I2C connections easier.


UXplor-Breakout - If you only need power and pins, that is the UXplor-Breakout. It provides power from a USB connection and a LiPo battery (3.7v). The host side is spaced for standard 2.54mm breadboard pitch.

The next generation of UXplor-Breakout will have both 5v to 3.7v regulator and a LiPo charger circuit. This change allows you to eliminate the LiPo if your power source can provide a transient 2A supply.

The header provides the signal connections to\from the modem and the host system.  The table below describes the signals present on the Host Interface (HI). See the photo below for reference in determining pin #1 on the header.

Pin (from left)
Signal Name
1VBATPowerPower in, standard 3.7 volt LiPo expected
2GNDPowerSystem ground
3MOSISignal-OutSPI data out (from host to CTA)
4MISOSignal-InSPI data in (from CTA to host)
5~CSSignal-InSPI chip-select (inverted logic, GND=true)
6CLKSignal-InSPI clock
7~IRQSignal-OutCTA IRQ (inverted logic, GND=true)
8AuxTXSignal-InAuxiliary serial out (host to CTA, if CTA supported)
9AuxRXSignal-OutAuxiliary serial in (CTA to host, if CTA supported)
10PwrKeySignal-InPower on/off (pulse to toggle CTA power state)
11ResetSignal-InResets modem
12~WakeSignal-InInstructs modem to wake
13StatusSignal-OutIndicates that the modem is powered on
14ConnSignal-OutIndicates that the CTA is connected
15EventSignal-OutWhen toggled, signals that the CTA has a new event
16N/ANot Connected

~ prefixed items indicates inverted signal (true when low)

Note: The logic level on the modem-to-host interface is 3.3 volt signals. 

There is also a micro-USB connector on the CTA that allows you to communicate with the BG96 module directly, bypassing the LTEm1's SPI-serial subsystem.  To communicate with USB to the LTEm1 you will need to have compatible USB drivers installed on your workstation. You can obtain the USB drivers for Windows here.  There is also a utility available to allow you to send commands easily called QCOM which is available here.

To use the USB interface for communicating with the LTE module directly you will have to select the AT virtual port on the USB interface. This is most easily determined by using the Windows Device Manager utility and expanding the list of Ports (see below). The 3 virtual ports on the LTEm1 USB interface are

  • Quectel USB AT Port - AT Command\Data
  • Quectel USB DM Port - Diagnostics\Firmware
  • Quectel USB NMEA Port - GNSS NMEA Sentence Output

Attaching the LTEm1 to a Host Adapter

To attach your modem board to any of the LooUQ UXplor development boards complete these steps. There is also a short video showing this process .

  • With the modem face up, carefully slip it onto the right-angled header until the pins of the nylon snap-fit supports align with the LTEm1’s 2 mounting holes (see image).
  • Push down to snap the supports into the CTA mounting holes.

To remove the CTA from the Host Adapter, carefully pull up on the modem board at the top (between the 2 snap-fit pins) until the modem is slightly above them.  Next, slide the modem board off from the host interface header.


LooUQ has developed an open-source driver library to make integration between your device IoT application and the CTA-LTEm1 as seamless as possible.  The full source code can be viewed and downloaded from the LooUQ GitHub site.

Full-details on the LTEm1c software driver are available in other Answers Center documents dedicated to the software.

Getting Online

To enable rapid access to network carrier communications and the online services this communication enables, LooUQ has partnered with Verizon to provide data plans of varying capacities.  By bundling LooUQ data-service plans with your CTA-LTEM1 modem, you can focus on  your project, not setting up and account and configuring device profiles.  The CTA-LTEm1 comes completed with a Verizon M2M (machine-to-machine) compatible USIM, regardless of whether you purchase your data service plan through LooUQ or you manage it directly in your own Verizon Enterprise account.

You can purchase the CTA-LTEm1 bundled or un-bundled with the following options...

  • Purchase the CTA-LTEm1 bundled with the LooUQ iotQi application enablement platform and Verizon data-service plan.  This allows you the most rapid IoT development path, delivering your IoT data directly to enterprise APIs and cloud storage.
  • Purchase the CTA-LTEm1 bundled with the LooUQ managed data-service plan. This allows you to focus on your IoT application without the requirement to provision and manage options for your plans, just determine the required bandwidth capacity and hit the road running.
  • Purchase the CTA-LTEm1 stand-alone.  If you already have an existing Verizon Enterprise account and are comfortable updating your profile and adding devices, this option allows you acquire the CTA-LTEm1 (including USIM) and manage everything yourself.

BG96 Module Tools and Documentation

The CTA-LTEm1 uses a Quectel BG96 module for cellular communications and GNSS signal processing. While we recommend that you utilize our advanced driver software to integrate the modem with your IoT device application, there maybe times you want to learn more about the BG96 or want to implement AT commands yourself.  For those occasions there are some resources we can offer.

You can access the support files for the Quectel BG96 after your register with Quectel.  Access to the Quectel BG96 support files are available here.



For Power Specifications please see the Power Requirements section above.

  • 45mm x 40mm x 9.15mm PCB
  • 48mm x 40mm, including interface header
  • Temperature Range: -40°C ~ +85°C
  • 14 grams (0.5 ounces) with SIM installed
  • All dimensions on diagram above are in mm
  • Top components: in blue, bottom components: in gray
  • Clearance: 
    • Top: 3.1mm (C6, C10), 2.3mm (module)
    • Bottom: 4.9mm (CTA-HA header), 2.75mm (USB), 2.25mm (SIM holder)

Operation and Storage Temperatures

  • Operation Temperature Range -35°C to 75°C, typical 25°C
  • Storage Temperature Range -40°C to 90°C

Host Communications

  • Logic Level: 3.3-volts

Wireless Communications

  • LTE Cat M1, LTE Band 13, 700 MHz
  • Maximum Power: 23dBm
  • Sensitivity: -107dBm @Cat M1, 1.4MHz Bandwidth, CE