1771-iad the allen-bradley / rockwell automation 1771-iad is a general-purpose 120v ac/dc input. Operating voltage for 1771iad is 79...138v ac and 79...138v dc Best price+one year warranty+in stock+new+original 1771-iad the allen-bradley / rockwell automation 1771-iad is a general-purpose 120v ac/dc input. Operating voltage for 1771iad is 79...138v ac and 79...138v dc