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BlueBus

BlueBus is a Bluetooth interface module for BMW vehicles equipped with the I-Bus. It emulates a CD changer on the I-Bus to provide seamless Bluetooth audio, hands-free telephony, and comfort feature integration while maintaining full compatibility with original vehicle systems.

Supported Vehicles

BlueBus is compatible with BMW vehicles using the I-Bus architecture:

Platform	Models	Years
E38	7 Series	1994-2001
E39	5 Series	1995-2004
E46	3 Series	1997-2006
E52	Z8	2000-2003
E53	X5	1999-2006
E83	X3	2003-2010
E85	Z4	2003-2008
E86	Z4	2005-2008
R50/R52/R53	MINI	2000-2006

Features

Bluetooth Audio

• A2DP streaming with high-quality audio output over AAC
• AVRCP metadata display (artist, title, album) on vehicle screens
• Full playback control via vehicle buttons

Hands-Free Telephony

• HFP (Hands-Free Profile) with factory microphone integration
• Caller ID display on vehicle screen
• Answer/end calls via vehicle controls
• Telephone LED control (Red = Device Disconnected, Green = Connected)
• Voice recognition support via Siri / Google Assistant
• Emulation of OE telephone system (Minus the Menus, for now)

Vehicle Integration

• Native DSP compatibility (analog and S/PDIF inputs)
• On-Board Computer data display (coolant temp, ambient temp, oil temp)
• GPS time synchronization for vehicles with factory Nav
• Park Distance Control integration

Comfort Features

• Auto-lock at configurable speed threshold
• Auto-unlock on ignition off
• Comfort turn signals (Tap to signal)
• Parking lamp control

System

• Firmware upgradable via USB
• Multi-language support (9 languages)
• Up to 8 paired Bluetooth devices

Supported Display Units

Unit	Description	Display
BMBT	Board Monitor (Navigation)	Full graphical menus
MID	Multi-Information Display	24-character single line
CD53	Business CD Radio	11-character single line
MIR	Multi-Information Radio	Single line display

Hardware

Core Components

Component	Description
PIC24FJ1024GA606	16-bit MCU @ 16MHz, 1MB Flash
BM83	Microchip Bluetooth 5.0 Module
Melexis TH3122.4	I-Bus Transceiver

Audio Chain

Component	Description
PCM5122	Line-Level DAC, 2.1V RMS, 113 dB SNR
DIT4096	S/PDIF Encoder
PAM8406	5W Class-D/Class-AB Amplifier

Interfaces

Component	Description
FT231XS	USB to UART (firmware updates)

Configuration

Settings are stored in EEPROM and can be configured through the vehicle display menus. Categories include:

• Audio - DAC gain, DSP input source, volume offsets
• Telephony - HFP mode, microphone gain, volume
• Comfort - Auto-lock speed, blinker count, lighting options
• UI - Language, temperature units, display preferences
• Navigation - Auto-zoom, map display mode