Wiring the TRRR Audio Connector

Step 2: Wiring the TRRR Audio Connector

Almost all smartphones expect the mike and common leads on connectors 3 and 4. Most follow the leader—the iPhone—and put common on ring 2 (connector 3) and the mike on ring 3 (connector 4.) There are reports that Droids reverse that. I’m not sure it makes a big difference, since we’re not going to connect the stereo outputs anyway. However, the shield of the audio cable is probably better off on “common.”

Begin by soldering a roughly 1’ length of audio cable to the connectors for the middle and bottom ring of the 4-conductor audio plug. The bottom ring (furthest from the tip) goes to the largest connector. If you’re not going to get all fancy with RCA audio jacks and plugs, just tin or solder a short solid wire to the other ends so that they stick more easily into the protoboard. Do the same with a 1-2’ audio cable for the alligator clips and the leads for the switch(es). Be sure that the alligator clip connected to common is identified as such. When ready you can cut down the breadboard to fit in your plastic box, leaving the rest for other projects.