I am seeing Mylaps transponders advertised as '2 wire' and '3 wire' .. besides having another wire, what are the differences, and any benefit/detriment of using either? ... thanks!

The "3-wire" are the newest, and only work with a Mylaps decoder that has the Rc4 software.

The "2-wire" is the hybrid model, and works with the older RC3 software and the newer RC4.

You will find that the price is a little more for the "2-wire" as it is covers more decoder possibilities.

You kinda need to know what firmware the tracks you are running at have on their decoders, or just play it safe and get the "2-wire"

Thanks, brew ...

.. and how do the older AMB brand/style 2 wire transponders fit into what works/doesn't work with current systems ?

The older AMB transponders still work with the newest decoder RC4 firmware, so no issues.

If you know you will only attend a track that has the newest firmware, then the "3-wire" would be sufficient. If you possibly could be going to a track that hasn't upgraded their firmware, it's best to get one of the older version transponders (2-wire)

They're fine. I have 4 of them

.. perfect! .. thanks guys