- PCE PCE-DM32: Briefly press the "RS232" button.
- RadioShack 22-812: Press and hold "SELECT" and "RANGE" together.
- TekPower TP4000ZC: Briefly press the "RS232" button.
- - UNI-T UT61C: Press the "REL/RS232/USB" button for roughly 1 second.
- - UNI-T UT61D: Press the "REL/RS232/USB" button for roughly 1 second.
+ - UNI-T UT61B/C/D: Press the "REL/RS232/USB" button for roughly 1 second.
- UNI-T UT325: Briefly press the "SEND" button (as per manual). However, it
appears that in practice you don't have to press the button (at least on
some versions of the device), simply connect the device via USB.