access to usb pins on teensy 4.1


Well-known member
Hi all,
Quick question/confirmation that the only access to the primary USB connection on the teensy 4.1, other than the USB micro connection, is via the 2 pads below (D+ & D-) below the USB micro connector? The teensy will be mounted to a PCB inside a case and looking to "extend" the USB connection to a socket on the case without too many sockets/connections inside the case for ease of programming/updating firmware. For example, would love to be able to use something like this:
then connect the data and power pins in the socket directly to the teensy.

Thanks in advance for any guidance.

There are male Micro to female USB cables - panel mount or other perhaps - PJRC used to stock one - just linked one the other day.

That would take some room - but avoid soldering and any troubles with the T_4.1's higher 480 Mbps transfer rate.
Great. I've been looking at those, too. Just wanted to make sure the USB pins weren't broken out elsewhere on board and hiding from me :)
The 2 small test points on the bottom side of Teensy 4.1, underneath the main USB connector, are indeed the D+ and D- signals. Teensy 4.0 and very early beta 4.1 test boards didn't have those 2 pads, due to concern for the 480 Mbit speed signal integrity. But it turned out they don't cause a problem, so they did make it onto the final Teensy 4.1 design.

But those 2 signals are for the main USB port which is only supported in USB device mode. That SS-52100-001 connector is a USB type A female, which is only appropriate for USB host mode. You would need to connect that to the 2nd USB port, which is on the 5 through-hole pins on Teensy 4.1, or as data-only pads on the bottom of Teensy 4.0.
Hi Paul,
Thanks for your help with this. The teensy will only be working in usb device mode for this application. Most of the communication to/from will be via RS485 and the fancy new network option you've added to the 4.1. 99% of the time the teensy won't be connected to any host via USB. This is only for the infrequent times we need to update the firmware but don't want to open the case...pretty much an extender from the edge of the case to the micro usb socket on the t4.1.
Not sure that clarifies anything or not :)
Not sure that clarifies anything or not :)

Indeed that does give a better picture of what you're trying to accomplish.

But just because you don't normally need the main USB connector for device mode isn't going to magically make software appear to run it in host mode. The only software support for the main port is USB device mode. It is theoretically possible to create software to run the main port in host mode, if you're feeling like climbing a steep hill...

We do have USB host support for the 2nd port. And the 2nd port is easily available from either side of the PCB on 5 though-hole pins. So I'm a little confused about why you wouldn't want to just use the 2nd USB port?
Sorry, I feel like I'm confusing myself. I don't need the teensy run as a USB host. I only need need the usb connection to upload new firmware from a laptop as needed/after the device is "in the field". I've also been reading here on the forum how to update the firmware via network/other means instead of USB, just as an alternative.

The panel mount USB-B cable looks to be a viable option.

Thank you all again,
Do not use that SS-52100-001 connector.

This connector is used for USB host mode only!