IBM PCjr - Technical Specifications

Technical Specifications

• CPU: Intel 8088, 4.77 MHz
• Memory: 64K on the motherboard expandable to 128K via a card in a dedicated slot. Further expansion via IBM sidecar adapters. Later third-party add-ons and modifications raised the limit to 736K.
• Operating system: IBM PC-DOS 2.10, (Boots to Cassette BASIC without cartridge or DOS)
• Input/Output: cassette port, light-pen port, two joystick ports, RGB monitor port, composite video port, television adapter output port, audio port, wired keyboard port, infrared keyboard sensor, serial port, two cartridge slots
• Expandability: 3 internal slots, dedicated to PCjr specific memory, modem (300 bits per second non-Hayes-compatible modem available from IBM, although 2400 bit/s Hayes-compatible modems were available from third parties), and floppy controller cards. External sidecar connector capable of daisy-chaining multiple sidecars.
• Video: Motorola 6845, "CGA Plus" This chip was officially called the VGA (Video Gate Array).
  • Text modes: 40×25, 80×25, 16 colors
  • Graphics modes: 320×200×4, 640×200×2, 160×100×16, 160×200×16, 320×200×16, 640×200×4
  • Video memory is shared with the first 128 KB of system memory, and can be as small as 2 KB and as large as 96 KB.
• Sound: Texas Instruments SN76496; three voices, 16 independent volume levels per channel, white noise
• Storage: Optional 5.25 inch diskette drive or cassette. Other storage options were provided by third parties.
• Keyboard: 62 key detached. Corded or infra-red operation. IBM supplied two different keyboards, the first being the maligned 'Chiclet' keyboard, so named for its square rubber keys that resembled Chiclets. Many third-party keyboards were also available.