The RHTx-SMS-4G is a Server Room Temperature and Humidity Monitoring System designed to send real-time readings and alerts via SMS over 4G/LTE networks. It is ideal for continuous environmental monitoring in data centers, seed storages, warehouses, greenhouses, and pharmaceutical facilities where reliable communication and accurate sensing are critical. This upgraded version replaces the earlier 2G model, offering 4G/LTE connectivity with backward compatibility to GSM networks. The device can send Periodic SMS updates at user-defined intervals, Alert SMS when set limits are breached, and On-Demand SMS reports upon request from registered mobile numbers — all without requiring any internet connection or data plan. Equipped with a high-accuracy temperature and humidity sensor, a graphical LCD display with white backlight, and a built-in buzzer alarm, the RHTx-SMS-4G ensures prompt detection and notification of environmental changes. Users can freely configure alarm limits and acknowledge alerts directly through the front keypad. Built in a rugged ABS plastic IP65-rated wall-mount enclosure, the instrument operates reliably in demanding industrial conditions. It comes complete with a factory calibration certificate, power adaptor, and LTE antenna for easy installation and dependable performance.