The machines have two printers which can print on, and encode the magnetic stripes on the rear of, Rail Settlement Plan-accredited ticket stock. This has a batch code of RSP No. 9399 and consists of fanfold (concertina-style) packs of round-cornered tickets joined to each other by perforated lugs which are cut during the printing process. An experimental ticket stock with diagonal corners was used in the earliest trial machines. In common with other "New Generation" (post-privatisation) ticket issuing systems, the ticket stock has no pre-printed data other than some conditions on the reverse; all data is printed by the machine. Machines accept either payment cards only or both cards and cash. On the latter, banknotes and coins are checked electronically. Keypads for Chip and PIN card payments were fitted retrospectively on older machines, and as standard on newer machines, when this technology was introduced.