Some basic questions about bluetooth communication

Started by lk_517 March 13, 2009
Hi all:

I am a newbie about Bluetooth development, I am debugging a board which
contains bluetooth chip(LMX9838), and have some questions about the
principle, I will be very appreciate if anyone can answer all or part of my

1 The is a mode called "transparent master/slave", my understanding about
this mode is, if I have two bluetooth module, and make them both work in
this mode, they can exchange data with each other directly without the need
of command formation interpret.

However, most mobile devices as well as desktops don't have this mode, at
lease I don't know how to open it.

2 In my case, the bluetooth module on board is used to communicate with
mobile device, not with another module on board. I just found "file
transfer" function on the device, does it mean that I can only communicate
with mobile device in the form of "file" rather than raw message sending or

3 If so, what kind of service should I use? LMX9838 supports Generic
Access profile (GAP), Service Discovery Profile (SDAP) and
Serial Port Profile (SPP). Now spp link has been set up on the module on
board, but I have no idea what should be the next step? More specifically,
which step is required if I want to send file from the module to mobile

4 The last question is a chip specific question. When I send inquiry in
order to get the name of remote device, I always can only get part of the
name, even though the returned "length" value is right. Which means, I know
the name will be 10 character length, but I can only get 5 character from
the serial port, then the serial port is just keeping reading and never
return the complete name of remote device. I can do some trick to avoid the
endless waiting, like assigning the loop times manually to 3 times or
something like this. But I am really curious about the reason. 

Again, I will be very appreciate if anyone can answer all or part of my
questions. Thanks for all the guys who is patient enough to achieve here.

By Armstrong.