Make:

If it stopped working, maybe it is as simple as replacing your battery?

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I'm getting a kick out of the fact that whoever laid out the board put R2 right next to D2.

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TIRIS:

Texas Instruments Registration and Identification System

http://www.pcmag.com/encyclopedia_term/0,2542,t=TIRIS&i=52932,00.asp

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I've worked with these systems in the past, and am familiar with similar systems used in N.Y. N.J, Boston, Georgia, and California.

Most of these transponders support an "Industry Standard" protocol, as one or more propietary ones. For the most part, the industry standard is avoided to make it more difficult for the customer to migrate to a competitor's hardware.

Each toll lane has a lane controller pc with serial ports and DIO ports for communicating with the transponder reader, gates, signs, etc. The transponders operate in passive-active mode, so they usually require the antenna in the toll lane to send an unattenuated signal to turn on the tag. When the tag turns on, it attenuates the signal, encoding is serial number, and checksum back to the lane controller.

The reader unit is also in a passive-active state controlled by magnetic loops in the road, or in some cases, ir light curtains.

Seriously, Electronic Toll Systems are lot of fun to work on.

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Oh, I almost forgot! The tags have a life expectancy of 5 to 7 years, on average. I modded one to work off solar that a vendor provided in a clear case (ours were black or green).

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The battery is in fact dead. Before now I had always assumed these were powered by the reader and had no internal battery, but I guess the piezo buzzer gives it away. This one lasted about 4 years.

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Is that battery an off-the-shelf deal?

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