# Wiring

Internal electrical TPA2 connection resembles simple switch with normally connected contacts. After stylus is actuated, contacts become disconnected. Signals are isolated from instrument body.

[![wiring2.png](https://wiki.kurokesu.com/uploads/images/gallery/2021-03/scaled-1680-/wiring2.png)](https://wiki.kurokesu.com/uploads/images/gallery/2021-03/wiring2.png)

<table border="1" id="bkmrk-pin-function-1-not-u" style="border-collapse: collapse; width: 100%; height: 145px;"><tbody><tr style="height: 29px;"><td class="align-center" style="width: 50%; height: 29px;">**Pin**</td><td class="align-center" style="width: 50%; height: 29px;">**Function**</td></tr><tr style="height: 29px;"><td class="align-center" style="width: 50%; height: 29px;">1</td><td class="align-center" style="width: 50%; height: 29px;">Not used (unconnected)</td></tr><tr style="height: 29px;"><td class="align-center" style="width: 50%; height: 29px;">2</td><td class="align-center" style="width: 50%; height: 29px;">Signal</td></tr><tr style="height: 29px;"><td class="align-center" style="width: 50%; height: 29px;">3</td><td class="align-center" style="width: 50%; height: 29px;">Signal</td></tr><tr style="height: 29px;"><td class="align-center" style="width: 50%; height: 29px;">4</td><td class="align-center" style="width: 50%; height: 29px;">Not used (unconnected)</td></tr></tbody></table>