- 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.
+ - Tenma 72-7750: Briefly press the "RS232C" button.
- UNI-T UT60G: Briefly press the "RS232C" button.
- 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