Asus TS300-E7/PS4 - Manual (Page 63)

ASUS TS300-E7/PS4 4-11
4. USB connector (10-1 pin USB34, USB56; A-Type USB7)
These connectors are for USB 2.0 ports. Connect the USB module cables to
connectors USB34 and USB56, then install the modules to a slot opening at
the back of the system chassis. These USB connectors comply with USB 2.0
specification that supports up to 480 Mbps connection speed.
5. Thermal sensor cable connectors (3-pin TR1)
This connector is for temperature monitoring. Connect the thermal sensor
cable to this connector and place the other end to the device, which you want
to monitor temperature.
You can connect the thermal sensor cable to either pin 1-2 or pin 2-3.