The Atom DTU NBIoT2 v1.1 is an NB-IoT programmable wireless data transmission unit (DTU) for global Cat-NB bands. It add a IO expansion chip, enabling control over the communication module's power enable and software reset, reducing power consumption and ensuring SIM module reset without power interruption in case of module malfunctions. Additionally, a ADC monitoring circuit is added to support real-time acquisition of the power supply voltage input to the HT3.96-4P interface for power status monitoring. This unit integrates a SIM7028 communication module, employing serial communication (controlled via AT command set) and an integrated SMA external antenna interface, offering excellent communication quality and signal stability. The SIM7028 module covers multiple Cat-NB frequency bands for global use. Compared to typical DTUs that only offer data pass-through functionality, the Atom DTU adopts a more open architecture design, reserving multiple interfaces (RS485, I2C/custom Grove interface) for user expansion, facilitating rapid connection of sensors and actuators. The built-in rail clamping structure allows for embedding in various industrial control environments, suitable for applications in low-latency, low-throughput scenarios such as remote control, asset tracking, remote monitoring, telemedicine, and shared bicycles. Specifications: Communication Module: Supported Cat-NB Bands: SIM7028B1/B2/B3/B4/B5/B8/B12/B13/B14/B17/B18/B19/B20/B25/B26/B28/B66/B70/B85 Network Protocols: TCP/UDP/HTTP/TLS/DTLS/DNS/NTP/PING/LWM2M/COAP/MOTT/MOTTS/SSL Carriers: Deutsche Telekom/Vodafone/Telefonica/China Telecom/China Mobile/China Unicom Communication Method: UART 115200bps @ 8N IO Expansion Management Chip: M5IOE1 Antenna Specifications: Dimensions 108x10mm, Interface Type SMA (Internal Screw), Operating Frequency Band 850~1900 MHz, Gain 2.0 ± 0.5, VSWR ≤ 3.0 Power Supply: RS485 port (HT3.96R-4P interface): 9~24V; USB Type-C: 5V Power Consumption: SIM module power off: 24V@9