This blog post provides a detailed demonstration of connecting an Arduino to a GSM/GPRS network using a Seeed Studio GPRS Shield and PubNub, illustrating the process of enabling mobile IoT applications in environments without WiFi access. It begins with essential steps such as setting up a SIM card with a data plan, importing necessary libraries, and using Arduino's software serial to communicate with the SIM900 chip. The post highlights challenges, like insufficient power from a single USB supply for TCP requests, and offers solutions such as adding C cell batteries. Once configured, the article explains how to use PubNub’s REST Push API for bidirectional data streaming, using demo keys to facilitate communication between devices via a public channel. The guide emphasizes the importance of properly configuring network-specific settings, such as APN, username, and password, to establish a successful internet connection, while also utilizing the PubNub console to monitor data transmissions.