Smith admits he signed without discussing personal terms.
"I wasn't interested in it because I wanted to come here," he told the Nottingham Post. "As soon as I spoke to Shaun and (assistant) Greg Abbott my decision was made."
Smith, 33, added: "I'd spoken about going further afield to America, but it never really appealed to me because there's no promotion or relegation and I don't like playing for fun.
"I just got the right feeling when I came here. The one thing Shaun wants to install in the club is the right mentality. Once he said that to me that was enough."
For the big stories and the banter follow us on Twitter: @tribalfootball