In addition to cell phones, what other electronic devices might diffuse rapidly to developing countries because of low cost of equipment and lack of need for costly infrastructure?

Radios, laptops

Explanation:

Radios will most definitely diffuse rapidly, as indicated from the question, into developing countries because of the important and vital role they play in sending information to areas of isolation. Laptops and maybe tablets will also diffuse into developing countries rapidly because of the over-reliance on the internet for information and these are electronic devices that can be used to access the internet easily.