Symbol MC9000-K/S Reference Manual page 560

15-8 MC9000-K/S with Windows
Table 15-2. Troubleshooting Bluetooth Connection (Continued)
Problem
Piconet (the connection
between a Bluetooth master
and one or more Bluetooth
slaves) drops.
My application created a
successful RFCOMM session
with another Bluetooth device
but the RFCOMM session was
dropped.
After completing an RFCOMM
session with another Bluetooth
device, I was unable to create
a virtual COM port to connect
to another Bluetooth device.
®
Mobile 2003 Software for Pocket PCs PRG
Cause
When the mobile computer suspends,
and the Bluetooth radio power is
turned off, piconet is dropped.
One of the devices may be out of
range.
Device went out of range or was shut
off.
The Microsoft Bluetooth stack holds a
baseband connection for ten seconds
after an application closes its session
and exits. This was designed to allow
for speedy connections to the same
device if other profiles were to
connect.
Solution
An application can register for notification of a
mobile computer resume by creating a message
queue using the CreateMsgQueue() API and
power notifications using the
RequestPowerNotifications() API (refer to the
SMDK Help File). After an application receives
a resume notification it should close previously
open Bluetooth sessions and reopen them.This
reestablishes the piconet lost during the
suspend.
Check the return value of APIs for errors. Look
for a DCD state change event in the Microsoft
Bluetooth stack DCD window of the Bluetooth
connection.
Either wait 10 seconds, choose a different COM
port number for the virtual COM port, or modify
HKLM\software\Microsoft\bluetooth\l2cap\Idle
Phys (which defines the number of seconds to
hold the connection).