--- title: Kaypro 4 categories: - Computers types: - Transportable origins: - U.S.A. years: - '1984' cpus: - Z80A params: name: Kaypro 4 image: /media/museum/photos/kaypro_4_system_s1.jpg logo: /media/museum/logos/kaypro_4_logo_s1.jpg company: /companies/kaypro company_name: Kaypro specs: - label: NAME value: Kaypro 4 - label: MANUFACTURER value: Kaypro - label: TYPE value: Transportable - label: ORIGIN value: U.S.A. - label: YEAR value: '1984' - label: END OF PRODUCTION value: '1985' - label: KEYBOARD value: Detachable, 72 key typewriter style keyboard with 18 programmable keys. - label: CPU value: Z80A - label: SPEED value: 4 Mhz - label: CO-PROCESSOR value: Motorola 6845 (video controler) - label: RAM value: 64 KB - label: VRAM value: 2 KB - label: ROM value: 2 KB - label: TEXT MODES value: 80 chars x 25 lines - label: GRAPHIC MODES value: virtual 160 x 100 through graphical characters - label: COLORS value: built-in 9'' non-glare green phosphor screen - label: SOUND value: No sound - label: SIZE / WEIGHT value: 46 (W) x 41.5 (D) x 21.5 (H) cm / 15kg - label: I/O PORTS value: Two RS-232C serial ports, one Centronics-type parallel port, communication socket (built-in modem) RJ11C modular telephone jack - label: BUILT IN MEDIA value: two 5.25'' DS/DD half-height floppy drives (390 KB) - label: OS value: CP/M 2.2 - label: POWER SUPPLY value: Built-in power supply unit - label: PRICE value: About $3500 tabs: - photos - links - docs forum_thread: 542 photos: - title: LARGE VIEW subtitle: '' text: '' image: /media/museum/photos/kaypro_4_system_s2.jpg - title: SIDE VIEWS subtitle: '' text: '' image: /media/museum/photos/kaypro_4_bothsides_s1.jpg - title: CLOSED subtitle: '' text: When closed, the Kaypro rests on its keyboard. image: /media/museum/photos/kaypro_4_closed_s1.jpg - title: REAR PANEL subtitle: '' text: |- **(1)** Reset switch\ **(2)** Phone cord RJ11 connector\ **(3)** Parallel printer connector\ **(4)** First serial port\ **(5)** Second serial port intended for a serial printer\ **(6)** Keyboard RJ11 connector\ **(7)** Display brightness knob. image: /media/museum/photos/kaypro_4_rearpanel_s1.jpg - title: OPENED subtitle: '' text: All the Kaypro series - from Kaypro 1 to Kaypro 16 has the same internal layout. image: /media/museum/photos/kaypro_4_opened_s1.jpg - title: MOTHERBOARD subtitle: '' text: |- **(1)** Signetics 6545 video chipset\ **(2)** 2 x Z80 SIO chips in charge on one serial port each\ **(3)** Built-in modem circuitry\ **(4)** Real-time clock IC (MM58167) powered by the rechargeable battery that is soldered on the board\ **(5)** Zilog Z80 PIO in charge of the parallel interface\ **(6)** Western Digital floppy-disc controller chipset\ **(7)** Zilog Z80A processor\ **(8)** System ROM. Allows the system to load the OS from the diskette when switched on\ **(9)** 64 KB user RAM (8 x 4164)\ **(10)** Custom chip dedicated to the memory management\ **(11)** 4 KB Video RAM chips (2x2116)\ **(12)** Character generator ROM image: /media/museum/photos/kaypro_4_mainboard_s1.jpg - title: DISMANTLED subtitle: '' text: Dismantling a Kaypro computer is quite easy, provided that you carefully write down the location of each connector and the way they are connected. image: /media/museum/photos/kaypro_4_dismantled_s1.jpg - title: MANUALS subtitle: '' text: Kaypro shipped its computers with a large bunch of software and manuals. image: /media/museum/photos/kaypro_4_manuals_s1.jpg links: - title: Web Wiz CAPTCHA url: http://www.webwizcaptcha.com text: '' docs: - title: KAYPRO TECHNICAL MANUAL url: null cover: /media/museum/docs/couvs/kaypro_technical_manual.jpg text: |- **KAYPRO TECHNICAL MANUAL**\ written by Kaypro  compiled/archived by Unknown\  type of document : Online reader **... READ THE ONLINE VERSION BY CLICKING BELOW :** related: - /museum/kaypro-1 - /museum/kaypro-10 - /museum/kaypro-2x - /museum/kaypro-ii - /museum/kaypro-iv - /museum/kaypro-robie oc_id: 548 source: url: https://web.archive.org/web/20230329011529/http://www.old-computers.com/museum/computer.asp?c=548 date: '2023-03-29' --- This is the Kaypro 4 released in 1984, usually refered as **Kaypro 4/84**, as opposed to the [Kaypro IV](/museum/kaypro-iv/) released one year earlier, and refered as **Kaypro IV '83**. The main differences between the Kaypro 4 '84 and the Kaypro IV '83 were :\ \- A faster CPU, Zilog Z80A running at 4Mhz,\ \- A real time clock which can be used by programs (uses National MM58167),\ \- A better built-in monitor resulting in a very sharp display. The character matrix has also evolved from 5 x 7 on the Kaypro II and IV '83 to 8 x 16 pixels on the Kaypro 4 '84,\ \- the system had rudimentary graphics through graphical characters resulting in a virtual 160 x 100 resolution,\ \- characters could be displayed using two brightness levels and reverse attribute,\ \- the new prompt was a blinking square,\ \- like on modern keyboards, J and F keys were slightly different in shape from the other keys, so it was possible to spot them while staring at the screen,\ \- there was a built-in modem (300 baud, Bell System 103 compatibility, uses Texas Instruments TMS99537/TMS99532),\ \- the system had two DS/DD half-height floppy drives (390 kb) The system was bundled with Wordstar, dBase II, MicroPlan, Microsoft Basic, S-Basic, SuperCalc, C-Basic and CP/M 2.2 ! In 1984, in order to be compatible with IBM software, a special version was marketed with an Intel 8088 CPU in addition of the Z80A. It was called **Kaypro 4 Plus 88**! --- **Walter J. Dickie** reports:\ The Plus 88 was a dual-processor machine. First you booted up in CP/M, then inserted an MS-DOS (not PC-DOS) disk and booted the 8088. The really slick thing about the Plus was that in CP/M you could run the 8088 and it's associated 256K of RAM as a ramdisk. My standard boot routine involved booting in CP/M, firing up the 8088 as a ramdisk, copying all the WordStar overlay files onto the ramdisk (they just fit), then running WordStar on the Z80. With WordStar calling its overlays from the ramdisk the damn thing just flew!