Schematic symbol?

[teensy3056]

At the bottom of the Teensy® 3.6 Development Board page is the board schematic.

On it are two similar looking symbols with which I am not familiar, viz.,



and,



What do they mean or represent? On the second, what is the significance or meaning of the 'H' at the top and the 'D' at the bottom?

 

[MichaelMeissner]

Those are solder pads that may be connected, but that with a knife you can disconnect them.

The top one is the connection between VUSB and VIN. Normally VUSB is connected to VIN to power the Teensy from the USB cable. If you cut the solder bridge, you will need to apply 5v separately to the Teensy. See the comment at the top of the 3.6 pinout card (https://www.pjrc.com/teensy/pinout.html).

The bottom is the connection for power between the USB host pins and the USB power. Normally the USB cable to the Teensy powers the USB host pins. But if you cut the solder pad, and join the other pad, then the Teensy will draw power from the USB host connection. On the pinout card at the bottom on the right, it mentions this (H is host, i.e. the Teensy, D is the device).