Specifications

Windows Embedded Automotive 7 Deep Dive: Phone Core and Media Core 33
Table 8: Phone feature support
Feature
Description
Signal Strength
On phones which support signal strength reporting over Bluetooth, Windows Embedded
Automotive 7 reports this value to the user.
Roaming
Report
On phones which have a roaming indicator available via Bluetooth, Windows Embedded
Automotive reports this value to the user when paired with a platform having the
appropriate display.
Battery Level
On phones which have a battery level indicator available via Bluetooth, Windows
Embedded Automotive 7 reports this value to the user.
Power
Management
Windows Embedded Automotive 7 will transfer audio to the Bluetooth phone and
disconnect Bluetooth devices when power to the Windows Embedded Automotive 7
device is turned off.
Phone Core Versus HFPAPI
Microsoft recommends that OEMs develop applications using the Phone Core API instead of
HFPAPI when possible to maintain timing and command order. Table 9 provides details on what
features the Phone Core API manages.
Table 9: Phone Core API feature management
API
Features
Phone Core
• In-process DLL which wraps HFPAPI messages and extends the base
service for applications
• Manages Bluetooth phone objects and API routing
• Manages Bluetooth phone CONNECT_AUTO and CONNECT_APP
• Manages SCO audio connections
• Manages ring types (in-band SCO, HQRT, embedded)
• Provides interfaces to handle an embedded CellCore module
• Provides connection failure cause (not paired or out of range)
Host subsystem
• In-process DLL interface to HFP service which provides call control
(call, ring, notifications, caller ID, answer, reject)
• HFP Service contains specific phone workarounds and fixes
High-Quality Ringtone
Motorola phones can use HQRTs, though they do not notify connected devices that they are
using HQRTs. Detection of HQRTs can take up to three rings and is configurable within the
registry. The phone application should track the proper ring type (SCO, HQRT, embedded) on a
per-connected phone basis.
HQRT can be configured using the following registry key:
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Automotive\PhoneCore
The HQRTOption key value is used to set HQRT. A value of 0 disables HQRT, and a value of 1
enables HQRT. The RIngCountToPlayLocalRingTone key value controls the number of rings that