THE BRONX - Jails across the city will be undergoing major changes for the first time in nearly 30 years.Every inmate will now have to wear a uniform, unlike current procedures where only convicted inmates are issued a jumper. According to correction officials, about 80 percent of the inmates that aren't convicted currently wear street clothes.Another change is that officials will now be able to record prisoner phone calls and monitor their mail. Officials have been able to do this, but previously needed a court warrant to carry out the surveillance. Prisoner advocates have opposed the changes for years even though the practices are common at jails across the country.