Instructables

Do you have to be "paired" for a bluetooth terminal communication ?


If I have two bluetooth devices, running as SPP or AVRCP, and they HAVE been officially paired at one point - so presumably each knows of the presence of the other, can you create a communication channel, if they are not now "officially" paired ?

I have a device  which can run SPP , but which can only store 4 pairing profiles, but which I would like to use with up to 40 devices - and if it can't I need to work out how to work around it.....

Steve

Foxtrot703 years ago
Hi Steve - From my understanding of USB device connections from a recent computer class I took it would appear that 256 connections are possible. I think the limitation might be memory. As I understand it, SSP is the Bluetooth emulation of a wireless RS232 line. Here is a link I think might be helpful I found 32.4.6 of this article to closely address your question. - Mike

http://www.freebsd.org/doc/handbook/network-bluetooth.html
steveastrouk (author)  Foxtrot703 years ago
AHA !
"By default, Bluetooth communication is not authenticated, and any device can talk to any other device. A Bluetooth device (for example, cellular phone) may choose to require authentication to provide a particular service (for example, Dial-Up service). Bluetooth authentication is normally done with PIN codes. A PIN code is an ASCII string up to 16 characters in length. User is required to enter the same PIN code on both devices. Once user has entered the PIN code, both devices will generate a link key. After that the link key can be stored either in the devices themselves or in a persistent storage. Next time both devices will use previously generated link key. The described above procedure is called pairing. Note that if the link key is lost by any device then pairing must be repeated."

That may answer the question: If I can keep the link key "offline", it might be possible to compare it when a device requests comms anyway.....

Steve