TA3 and TA5 look like the same tiny XLR until you try to mate them. One is three pins. The other is five. Grab the wrong cable and the lav is dead, the transmitter is fine, and you are the person holding both ends.
Lectrosonics lavs are TA5. TA4 is a different connector: Shure bodypacks and DC power on Sound Devices 8-series. This is the short version of which mini-XLR is which. For the rest of the connector family, start with Understanding Audio Cables, Part 1.
What a TA3 cable is
A TA3 is a three-pin mini-XLR. You will see it on some lavs, headset mics, and older or smaller recorders. It carries a balanced mic or line signal, same idea as a full-size XLR, just in a connector that fits a belt pack.
What a TA5 cable is
A TA5 is a five-pin mini-XLR. Lectrosonics transmitters use it for lavs (TA5F on the mic side). The extra pins handle bias / servo bias, so a TA3 lav into a Lectro jack is not close enough. It is a different wiring job.
Where TA4 actually shows up
A TA4 is a four-pin mini-XLR. Most Shure wireless transmitters take a TA4F lav. Sound Devices 8-series mixers use a TA4 for DC power, not as a mic input. If someone hands you a “mini-XLR lav” and you are on Lectros, count past four. You want five.
How to tell them apart in a hurry
Count the pins. Three, four, or five is the whole tell. If the bag is dark, feel for the extras or check the connector stamp. Do not force a TA3 into a TA5 jack, or a Shure TA4 into a Lectro. You will bend a pin and then you have two problems.
If you are building or repairing a cable, match that transmitter’s pinout, not just the connector shape. A Shure TA4 and a Lectro TA5 are not interchangeable, and brands do not all wire a given pin count the same way.
What to keep in the kit
Keep one known-good TA3, one TA4 (Shure), and one TA5 (Lectro) lav whip labeled on the connector, not the heat shrink you will lose. If a new lav shows up with no adapter, that is a booking question, not a set surprise.
Need a cable or a wireless kit in Dallas? See location sound rentals or ask booking.