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Tom Allebrandi

Tom Allebrandi Bio

I’ll let you know up front that I am not a dancer. As a drummer, I have a pretty good sense of rhythm and time. But, when I get on the dance floor… well, a robot doing “the robot” looks more lifelike. So, I’m only guessing about what happens at a formal dance club.

You may like to dance and therefore frequent “formal” dance clubs. I’m not talking about discos or a bar here; I’m referring to clubs where the purpose of the club is to provide a place where those who really love to dance can dress up and do so.

The evening begins with a social time where those who’ve come to the club mingle and meet prospective dance partners. When a couple decides to meet later in the evening for a dance, they exchange names, a tentative time to meet again, and a “code phrase”.

A “code phrase”? Let’s say that during the dancing portion of the evening a gentleman approaches you and identifies himself as “Harald”. There are a lot of people attending the club this evening and it’s possible that more than one “Harald” is present. This one however does not look the person you met earlier. You ask for the “code phrase” and this Harald doesn’t give you the right answer. Politely you send him on his way.

A few moments later another gentleman approaches, identifies himself as “Harald” and knows that the prearranged “code phrase” is “Blueberry Pie”. This is the Harald that you met earlier so the two of you head to the dance floor.

That’s a lovely story, but what does it have to do with Bluetooth®?

One of the least understood features of Bluetooth technology is a process known as “Pairing”. Part of the problem is that it is not easy to describe Pairing – or even why you want to “Pair” – in a few sentences in a user’s manual. Worse, the “technically correct” terminology tends to get misused in order to make it easier to describe what needs to be done.

In “correct” use of the terminology, the Pairing process results in two Bluetooth devices becoming “Bonded”. Because of that, some people refer to the process as “Bonding”. Also, there are those who will refer to a pair of Bonded devices as being “Paired”.

The instruction manual for a Bluetooth device may tell you to make one of the devices “Pairable”. Or, the manual may tell you to make one of the devices “Discoverable” by pressing three different buttons at the same time until a one the indicator lights flashes.

Confused yet? Don’t be.

At its simplest, the Pairing process is a lot like the social time at the dance club. During Pairing, two people (Bluetooth devices) meet for the first time and exchange their names (Bluetooth device addresses) and validate the “code phrase” (called a “Link Key”) that will let them identify each other in the future.

Later, when the Bluetooth devices connect (get ready to dance), they check each other’s device addresses (names) and verify that they share the same Link Key (”code phrase”). (In Bluetooth terminology this is called “Authentication”.) If everything checks out then the devices know that they are Bonded to each other (in other words, have agreed to meet for a dance) and continue to execute the application (Headset to phone, file transfer, etc.) that brought them together in the first place.

In other words, they start dancing.

** I would be remiss if I didn’t point out that I’ve really glossed over the technical details, specifically, the creation and later validation of the “Link Key”. That, plus “Discoverability” (as hinted at above), are topics for another Blue-tiful day.