National legislation requires that all voting machines must be accessible to the handicapped and many of Mississippi's machines don't fit the bill.
Secretary of State Eric Clark said he wants Mississippi to have a uniform system by 2006.
Clark's spokesman, David Blount, said that's only possible if Congress fully funds HAVA. He said some of the machines, like those using levers and punch cards, need to be changed because they aren't accurate enough.
The federal law also calls for machines to allow voters to correct a mistake or verify whether a voter wants to leave a choice blank. Blount says the older machines don't have those functions.
Last year, Hinds County became the first to purchase touch-screen machines.