IRXON BT578 Serial Bluetooth Adapter User Guides

1. Introduction

Thank you for purchasing the IRXON BT578 Serial Bluetooth adapter. This adapter is typically connected to a serial device via a DB9 serial port, enabling communication with a mobile phone or computer over Bluetooth. It eliminates the need for conventional RS232 serial cables, providing a wireless serial connection with greater freedom and convenience.

The adapter facilitates a wireless serial connection, transitioning from traditional serial communication methods. It can connect to Bluetooth-enabled devices such as desktop or laptop computers, Android, and iOS mobile phones and tablets.

Adapter Components:

• 1. Serial Data Activity LED (Green): Indicates RS232 serial communication activity (TX/RX).
• 2. Bluetooth Status LED (Blue): Shows Bluetooth connection status. It blinks when the adapter is discoverable and waiting for pairing/connection, and turns solid when a Bluetooth link is established.
• 3. Power/Charging LED (Red): Indicates power status. It is on when external power is connected and also acts as a charging indicator for the internal battery.
• 4. AT Command Button: Press and hold to enter AT command mode for configuration.
• 5. DB9 Male/Female Slide Switch: Allows selection between DB9 male and female interface modes.
• 6. Serial Port (DB9-Male): The physical DB9 male connector for serial communication.
• 7. Internal Battery Power Switch: Controls the internal battery power.
• 8. External MiniUSB Power Port: Used for connecting external power or charging the internal battery.

1.1 Features

• Supports Classic Serial Port Profile (SPP) and new generation Bluetooth LE (BLE).
• Communicates with PCs via Bluetooth SPP and with mobile phones via BLE.
• Can connect to female or male serial port devices using the DB9 connector or converter.
• A green LED indicates TX/RX activity of RS232 serial communication.
• Supports Pin 9 power supply (connect pin 9 to 3-6V and pin 5 to GND).
• Built-in battery and charging circuit, includes an external power/charging cable.
• Supports AT command settings for personalizing name, baud rate, etc.
• Built-in amplifier provides a typical wireless communication distance of up to 30 meters.

1.2 Package Contents

• BT578 Serial Bluetooth adapter x1
• DB9 male to female converter x1
• AC to USB power adapter x1
• USB to MiniUSB power/charging cable x1
• This User Guide x1

2. Specifications

2.1 Technical Specifications

2.2 RS232 Interface

The BT578 adapter features a DB9 male serial port. The Male/Female slide switch allows configuration for direct connection to female DB9 ports or use with the provided male-to-female converter for male DB9 ports.

Pins 1, 4, 6, 7, 8 are not connected.

2.3 Factory Settings

• Serial Port Baud Rate: 9600bps
• Serial Port Parity: None
• Serial Port Data Bit: 8
• Serial Port Stop Bit: 1
• Serial Port Flow Control: None
• Bluetooth Name (SPP): BT578_SPP (for desktop/laptop PC)
• Bluetooth Name (BLE): BT578_BLE (for Android/iOS mobile phone)
• Bluetooth SPP Pairing Password: 1234

Refer to section 4.4 for AT Commands to change these settings.

3. Hardware Structure

Detailed hardware structure information is provided in the diagrams on the first page.

3.1 AT Command Button

Pressing and holding the AT command button while a Bluetooth connection is active puts the adapter into AT command mode. Releasing the button returns it to the connected mode.

3.2 Power Supply

• External Power Supply: Slide the internal battery power switch to the 'external power supply' icon side. Connect the MiniUSB cable to a USB power adapter. The red LED will turn on, indicating the adapter is powered externally. The internal battery charges when connected to external power.
• Built-in Lithium Battery Power Supply: Do not insert the MiniUSB cable. Slide the internal battery power switch to the 'battery' icon side. The adapter will be powered by the internal battery. Sliding the switch to the other side shuts down the adapter.
• Pin 9 of DB9 Connector Power Supply: The adapter can be powered via Pin 9 of the DB9 connector by connecting it to a 3-6V source and Pin 5 to GND.

3.3 LED Status

• Power/Charging LED (Red): Illuminates when external power is connected. It also indicates battery charging status; the LED turns off when the internal battery is fully charged (approx. 2-3 hours charging time).
• Bluetooth Status LED (Blue): Blinking signifies the adapter is discoverable and awaiting pairing or connection. A steady blue light indicates an established Bluetooth link with a PC or mobile phone, ready for communication.
• Serial Data Activity LED (Green): Flashes when data is transmitted or received through the BT578's serial port. It remains steadily lit during continuous data streams.

3.4 DB9 Male/Female Slide Switch

The BT578's serial interface is a DB9 male connector. To connect to devices with a female DB9 serial port, slide the switch to the "M" side for direct connection. If connecting to a device with a male DB9 serial port, use the provided DB9 male-to-female converter and slide the switch to the "F" side.

4. Configuration

Before connecting the BT578 serial Bluetooth adapter to a serial device, it's often necessary to adjust its settings, such as the baud rate. The adapter's serial port baud rate must match the serial device's baud rate.

4.1 Hardware Preparation

Connect the adapter to a Windows PC's serial port using a DB9 converter, ensuring the DB9 Male/Female switch is set to "F". If your PC lacks a serial port, a USB-to-RS232 serial port cable can be used to create a COM port.

4.2 Software Preparation

Most serial port monitor programs can be used with the BT578 adapter. The guide uses IRXON's "BT578 Tester" program as an example. Download it from: http://www.irxon.com/download/BT578-Tester.rar. After extraction, run "BT578_Tester.exe".

The software interface allows COM port selection, configuration (Baud Rate, Data Bit, Stop Bit, Parity, Flow Control), and sending/receiving data. It also displays connection status and received data.

4.3 Testing AT Command

In the "BT578 Tester" program, select the correct COM port and configure its settings to match the BT578's serial port (default: 9600, N, 8, 1). Ensure the blue LED is blinking (indicating no Bluetooth connection). Click "Open Com", input the command AT in the data input box, and press "SEND". A successful test returns "OK" in the receiving area.

4.4 AT Commands

AT commands use uppercase English letters, with +, =, ? as symbols.

• Inquire/Change Serial Port Baud Rate and Parity:
  • Inquire: AT+BAUD=? (Returns e.g., OK+BAUD=9600,NONE)
  • Change: AT+BAUD=<baud rate>,<parity>. Baud rates: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. Parity: N (None, default), O (Odd), E (Even). Parity can be omitted to keep the current setting. Example: AT+BAUD=115200,E sets baud rate to 115200 and parity to Even.
• Inquire/Change Bluetooth SPP Broadcasting Name:
  • Inquire: AT+NAME=? (Returns e.g., OK+NAME=BT578_SPP)
  • Change: AT+NAME=<Bluetooth SPP name> (Returns OKsetNAME). Name can be up to 12 characters (letters, numbers, dashes, slashes).
• Inquire/Change BLE Broadcasting Name:
  • Inquire: AT+BNAME=? (Returns e.g., OK+BNAME=BT578_BLE)
  • Change: AT+BNAME=<BLE name> (Returns OKsetNAME). Name can be up to 12 characters.
• Inquire/Change Bluetooth SPP Pairing Password:
  • Inquire: AT+PIN=? (Returns e.g., OK+PIN=1234)
  • Change: AT+PIN=<password> (Returns OKsetPIN). Password can be up to 12 characters (letters, numbers). Default is 1234. Password is not needed for BLE connections.
• Inquire BT578's Bluetooth Address:
  • Command: AT+ADDR=? (Returns e.g., OK+ADDR=2C36FA2DCFA8)

5. Application

The BT578 serial Bluetooth adapter connects to serial devices via a DB9 port and communicates wirelessly with a computer (via Bluetooth SPP) or a mobile phone (via Bluetooth LE).

5.1 Preparation

Ensure serial port settings (baud rate, parity, data bits, stop bits) match between the BT578 adapter and the connected serial device. The default BT578 settings are 9600, N, 8, 1. Use AT commands (Section 4.4) to adjust if necessary.

Connect the BT578 adapter to the serial device using the DB9 connector. Use the provided male-to-female converter and set the Male/Female switch to "F" if the device has a male DB9 port.

Turn on the BT578 adapter and prepare for Bluetooth pairing. Note that the adapter cannot communicate with a computer and a mobile phone simultaneously.

5.2 Communicate with Computer via Bluetooth SPP

On a computer, search for Bluetooth devices and select BT578_SPP (not BT578_BLE). Send a pairing request and enter the password (default: 1234).

After pairing, check the computer's "Device Manager" for the assigned Bluetooth virtual COM port. In your serial device application, select this COM port. A Bluetooth link will be established (blue LED turns steady), enabling communication with the serial device.

5.3 Communicate with Mobile Phone via Bluetooth LE

For BLE communication, run a BLE-compatible app on an Android or iOS mobile phone.

• For iPhone: Install the "LightBlue" app from the App Store. Use it to communicate with BT578 by writing to characteristic FFE1 and listening for notifications.
• For Android Phone: Download and install the "ATBlue" app from http://www.irxon.com/download/ATBlue-EN.rar. Run the app, tap "SCAN" to find nearby BLE devices, select BT578_BLE, and establish a Bluetooth link. The blue LED will turn steady, indicating readiness for communication.

6. FAQ

Q: Program cannot get "OK" message from BT578 when sending AT commands. What is the problem?

Possible causes:

1. Incorrect serial port settings (number, baud rate, data bit, stop bit, parity, flow control) in the serial monitor program. Ensure they match the adapter's settings.
2. Serial port settings were changed via AT commands, but the computer's COM port settings were not updated accordingly.
3. The Male/Female slide switch is not set to "F" when connecting to a female DB9 port.
4. After a Bluetooth link is established (blue LED is steady), AT commands are treated as normal data. To force AT command processing, press and hold the AT command button while sending the command.

Q: What is the difference between SPP and BLE for BT578?

From a user perspective:

• User Interface: SPP provides a Bluetooth virtual serial port; BLE uses Bluetooth characteristics.
• Bluetooth Link Objects: SPP is typically used for connecting to computers; BLE is usually for connecting to Android or iOS mobile phones.

For more information, visit http://www.irxon.com/english/.