each scan line or extend the black areas around the screen to extend the game code's processing time. Regional releases of the Atari 2600 use modified TIA chips for each region's television formats, which require games to be developed and published separately for each region. All modes are 160 pixels wide. NTSC mode provides 192 visible lines per screen, drawn at 60 Hz, with 16 colors, each at 8 levels of brightness. PAL mode provides more vertical scanlines, with 228 visible lines per screen, but drawn at 50 Hz and only 13 colors. SECAM mode, also a 50 Hz format, is limited to 8 colors, each with only a single brightness level. Controllers The first VCS bundle has two types of controllers: a joystick (part number CX10) and pair of rotary paddle controllers (CX30). Driving controllers, which are similar to paddle controllers but can be continuously rotated, shipped with the Indy 500 launch game. After less than a year, the CX10 joystick was replaced with the CX40 model designed by James C. Asher. Because the Atari joystick port and CX40 joystick became industry standards, 2600 joysticks and some other peripherals work with later systems, including the MSX, Commodore 64, Amiga, Atari 8-bit family, and Atari ST. The CX40 joystick can be used with the Master System and Sega Genesis, but does not provide all the buttons of a native controller. Third-party controllers include Wico's Command Control joystick. Later, the CX42 Remote Control Joysticks, similar in appearance but using wireless technology, were released, together with a receiver whose wires could be inserted in the controller jacks. Atari introduced the CX50 Keyboard Controller in June 1978 along with two games that require it: Codebreaker and Hunt & Score. The similar, but simpler, CX23 Kid's Controller was released later for a series of games aimed at a younger audience. The CX22 Trak-Ball controller was announced in January 1983 and is compatible with the Atari 8-bit family. There were two attempts to turn the Atari 2600 into a keyboard-equipped home computer: Atari's never-released CX3000 "Graduate" keyboard, and the CompuMate keyboard by Spectravideo which was released in 1983. Console models Minor revisions The initial production of the VCS was made in Sunnyvale during 1977, using thick polystyrene plastic for the casing as to give the impression of weight from what was mostly an empty shell inside. The initial Sunnyvale batch had also included potential mounts