[maemo-developers] [maemo-developers] bi-di BT-link between two 770s

[From: Adam Laurie]

Aleksandr Koltsoff wrote:

> 3) Is using RFCOMM-sockets between the devices a suitable transport? (I'm 
> looking for something akin to TCP). It can be assumed that only one program 
> will be active on a device at one time that needs this, so I guess BT-MAC 
> address is enough to connect?

I've just done a quick proof of concept to see if you can simply use the 
existing rfcomm utility and create a serial connection over BT... In 
this scenario, my 770 was device A, and a laptop running Debian Sarge 
was device B.

On device A:

   hciconfig hci0 piscan
   rfcomm listen 12
   (Waiting for connection on channel 12)

On device B:

   hcitool scan
   (list of visible bluetooth devices)
   rfcomm bind 0 [BD_ADDR of device A] 12
   chmod a+rw /dev/rfcomm0
   cu -l /dev/rfcomm0
   (Connected.)

On device A:

   (Connection from [BD_ADDR of device B] to /dev/rfcomm12)
   (Press CTRL-C for hangup)
   chmod a+rw /dev/rfcomm12
   cu -l /dev/rfcomm12

Now everything I typed on device A appeared on B's screen, & Vice Versa, 
so yes, it would appear that rfcomm would be a very simple and 
appropriate transport.

> 4) Can all of this be done with a normal application installed via the AI on a 
> stock 770? (not requiring the user to reflash from the sales sw version)

You would need to write some wrappers to create the connections etc., 
but the BlueZ libs are already installed so that should be pretty 
straightforward.

> 
> So, mostly the questions arise from my lacking experience with BT-programming 
> and my lack of experience with the 770 sw.

I would get a copy of BlueZ from:

   http://www.bluez.org/

and check out the utils sources for clues on how to do BT stuff. It 
works exactly the same on the 770 as it does on a PC. All you'd need to 
do is the GUI and/or integration into the game(s).

cheers,
Adam
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