Furthermore, radio equipment must also comply with TSO's if it is required by regulation in a particular class of airspace or operation.
Lots of radios aren't TSO'ed like Microair and Icom's - Icom has usually had both versions on the market, one certified and one not. Interesting comment in the link you have posted about how non TSO'ed gear is ok if the entire aircraft is approved. That would mean that a GA registered LSA aircraft such as a Jabiru could be filled with non-TSO'ed instruments and as long as it's approved under ATSM LSA standards, it's all good ! (in fact, the are full of Chinese instruments!)