A group of specifications for facsimile (fax) machines conforming to a standard published by the Electronic Industries Alliance (EIA) in 1966 as EIA RS-328 and accepted by the ITU-T as the T.2 mode of operation. Now considered obsolete, Group I standards specified analog transmission with modems using double sideband modulation (DSB). Group I machines conforming to international standards use Frequency Modulation (FM), transmitting at two frequencies, with 1500 Hz pegged as the white frequency and 2300 Hz as the black frequency.The North American standards peg 1500 Hz as white and either 2300 Hz or 2400 Hz as black. As Group I machines used no compression mechanism, transmission was slow at about 4