HOW DOES IT WORK?

4G LTE 2 Click - Voice (for North America) is based on the LARA-R6401, a multi-band and multi-mode module from LARA-R6 series from u-blox, supporting LTE Cat 1 FDD and LTE Cat 1 TDD radio access technology (18 LTE bands), with 3G UMTS/HSPA and 2G GSM/GPRS/EGPRS fallback providing the ideal solution for uncompromised connectivity for the North American market. This Click board™ represents a data and voice solution with global coverage and all relevant MNO certifications, offering great flexibility and the support of voice/audio applications. Versatile interfaces and features make the LARA-R6401 ideally suited for a wide range of applications that require medium data speed, seamless connectivity, superior coverage, low latency, and streaming data such as asset tracking, telematics, remote monitoring, point-of-sale terminals, and more.

The LARA-R6401 module provides Voice over LTE (VoLTE) and Circuit-Switched-Fall-Back (CSFB) from LTE to 3G or 2G radio bearer for audio services users can access via an onboard 3.5mm audio jack. This audio interface is configurable through the AT commands to transfer digital audio data to/from an external device as an onboard audio codec.

This module requires a power supply of 3.8V. Therefore, the Click board™ incorporates an integrated buck (step-down DC-DC) converter, labeled as TPS7A7002 by Texas Instruments, which provides a stable 3.8V power supply, capable of mitigating voltage drops at the input when a high current peak appears (typically at the StartUp of the device). The module Ignition (Power-On) pin, labeled as PWR and routed to the RST pin on the mikroBUS™ socket, offers a switch operation to turn ON/OFF power delivery to the LARA-R6401.

The LARA-R6401 communicates with MCU using the UART interface with commonly used UART RX and TX pins with the hardware flow control pins UART CTS, RTS, RI (Clear to Send, Ready to Send, and Ring Indicator). It operates at 115200 bps by default configuration to transmit and exchange data with the host MCU through AT commands that u-blox provides. Besides the UART interface, the LARA-R6401 also allows the I2C interface to act as an I2C host, which can communicate with I2C local devices following the I2C bus specifications. This Click board™ is also equipped with a USB type C connector, available for diagnostic purposes only. The module is a USB device and can be connected to any USB host with compatible drivers.

Among its used pins, this Click board™ also possesses two additional LED indicators: the yellow LED labeled as STATUS, routed both to the mikroBUS™ AN pin (STS) and the LED, used to indicate the status of the network connection visually, and a red LED labeled as TX used to tell the transmitting status of the module.

The LTE cellular networks use spatial multiplexing antenna technology, allowing more than one antenna to be used for better reception of the specific frequency channel. For that reason, besides the primary TX/RX antenna, this Click board™ uses a secondary diversity RX antenna, which allows better signal reception. Alongside those SMA connectors, the 4G LTE 2 Click also has a Nano-SIM card slot that provides multiple connections and interface options alongside several test points labeled from TP1 to TP3, enabling easy reboot and testing of the module.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

SPECIFICATIONS