But how the technology will be used will differ from county to county. In Erie County, registered voters can go to any one of 37 voting centers to cast a ballot. But in Orange County, a major commuter hub northwest of New York City, voters cannot go to any of the county’s seven designated early polling places; each voter will have a designated site.

Orange County’s approach, which supporters of early voting say may discourage and confuse voters, is also being used in Westchester County, and at the 61 early voting sites in New York City, where the Board of Elections has long faced accusations of ineffectiveness.

Mr. Ryan, the board’s executive director, said the board decided to assign early voters to a designated location because it wanted to minimize the ballot variations — each election district has a unique ballot — that each center would have to produce on demand. This would also simplify a hand recount, if necessary.

In future elections, Mr. Ryan said, the board is aiming to allow early voters to cast a ballot at any polling site in their county.

He also noted another concern: Some of the early voting locations in New York City did not have sufficient electrical current to power the printers and tablets, requiring the use of high-powered generators.

Some parents are worried about security in schools, which will be open to voters for a full week while classes are in session. Gilberte Lal , a president of the parent-teacher association at her children’s school, Public School 116 in the Murray Hill section of Manhattan, said she was concerned that voters would be walking through the cafeteria during school hours to reach the polling site in the gym.