The RN42/RN42N module is a small form factor， lowpower， class 2 Bluetooth radio that is ideal for designers who want to add wireless capability to their products without spending significant time and money developing Bluetooth-specific hardware and software. The RN42/RN42N supports multiple interface protocols， is simple to design in， and is fully certified， making it a complete embedded Bluetooth solution. With its high-performance， PCB trace antenna （RN42） or external antenna （RN42N）， and support for Bluetooth EDR， the RN42/RN42N delivers up to a 3- Mbps data rate for distances up to 10 meters.

　　The RN42/RN42N module is managed through ASCII commands via the UART and/or PIO signals. A microcontroller unit （MCU） or host processor sends commands to configure module features， read status， and manage Bluetooth data connections. As shown in Figure 1-1， the UART TX and RX are required to communicate with module， and transfer data across Bluetooth SPP connection. Connecting the hardware flow control lines CTS and RTS is highly recommended for applications that transmits a continuous stream of data. The module can be configured locally via the UART or over-the-air. To support instant cable replacement， auto-discovery/pairing does not require software configuration. Additionally， the module supports auto-connect master， I/O pin （DTR）， and character-based trigger modes.