The HP-75C was the first pocket computer ever produced by HP who wanted a pocket book format (10攛 5? computer as powerful as a desktop. It can also be considered as the first organizer able to deal with a multiple alarms time schedule, to control real time peripherals and to memorize text files.
Its 48KB ROM contained a very complete Basic language and a light version of the spreadsheet Visicalc. Three slots allowed adding pre-programmed ROM modules (Maths, finance, word processor?
It integrated a card reader. The cards was manually slipped front of the magnetic head. Each card could stock 1.3 KB of information on 2 tracks (650 bytes each). The card information coding allowed great variations of the reading speed, due to manual handling.
The HP-IL (Interface Loop) interface allowed connecting as far as 30 peripherals simultaneously on the HP-75C. Amid the peripherals, one could find a display unit, printers, a modem, a tape recorder and all the HP-IL standard peripherals.
As always with HP, the manuals were very complete and pedagogical.
The HP-75D was released two years later. It added a wand and wand port. When used with the Bar Code ROM, the computer could scan CODE11, CODE39, UPC, and EAN codes. This made the computer useful for inventory control.
Hewlett Packard HP-75C
By 1982, Hewlett-Packard had made dozens of calculators, even programmable calculators, but the HP-75C is their first handheld portable computer. It's not their first computer though, that would be the HP-85 from 1980, two years earlier.
There is no built-in permanent data storage, but small magnetic cards can be used to load and save data. On the lower right face of the 75C is the card reader - just a slot where the tiny card is manually inserted and pulled out the right side by the user.
On the front are three expansion slots for tiny RAM or ROM cartridges to be inserted - additional user memory or applications can be added quickly and easily. The "C" in HP-75C is for "continuous memory" - it can access 120K total memory.
On the back is the HP-IL serial interface for external printers, data storage, and other devices.
Here is another HP-75, but disguised as the "AT&T Information Systems" computer, resting in the HP-82718A expansion pod. The pod (originally $875) has 64K additional system memory, a 300 baud modem, and software to support a light-pen (there is a light-pen port on the back of the computer).
Because of the light-pen option, this is not an HP-75C, it's an HP-75D (released in February 1984 for $1095).
HP-75 from old-computers.com HP-75C from R/S Programmable Calculators HP-75 from hp.com. "Reverse-Engineering the HP-75C" "My collection of HP calculators" HP-75C/D from The Museum of HP Calculators
It integrated a card reader. The cards was manually slipped front of the magnetic head. Each card could stock 1.3 KB of information on 2 tracks (650 bytes each). The card information coding allowed great variations of the reading speed, due to manual handling.
The HP-IL (Interface Loop) interface allowed connecting as far as 30 peripherals simultaneously on the HP-75C. Amid the peripherals, one could find a display unit, printers, a modem, a tape recorder and all the HP-IL standard peripherals.
As always with HP, the manuals were very complete and pedagogical.
主要参数编辑本段回目录
| Released: | September 1982 |
| Price: | $995 |
| Weight: | 1.5 lb / 737 g |
| Size: | 10" X 5" ( 25 X 12.5 cm) |
| CPU: | HP 8-bit (Capricorn) |
| RAM: | 24K, 16K user |
| Display: | 32 character LCD |
| Storage: | 1.4K magnetic cards |
| Ports: | HP-IL |
| 3 ROM/RAM ports | |
| Power: | 3 nicad AA cells |
| OS: | BASIC |
 |  |
| NAME | HP-75C / 75D |
| MANUFACTURER | Hewlett Packard |
| TYPE | |
| ORIGIN | U.S.A. |
| YEAR | 75C : September 1982 75D: 1984 |
| END OF PRODUCTION | 75C : May 1984 75D : 1986 |
| BUILT IN LANGUAGE | Basic interpreter, Visicalc spreadsheet |
| KEYBOARD | 64 keys. Each key is user-definable |
| CPU | 8 bits, called Capricorn |
| RAM | 16 KB |
| ROM | 48 KB |
| TEXT MODES | LCD display. 1 line x 32 chars. |
| GRAPHIC MODES | 160 x 9 pixels |
| COLORS | Monochrome |
| SOUND | Beeper |
| SIZE / WEIGHT | 25.4 x 12.7 x 3.2 cm. - Weight 737g. |
| I/O PORTS | HP-IL, 3 x ROM/RAM expansion ports |
| BUILT IN MEDIA | Memory cards, 1.3 KB |
| OS | Specific |
| POWER SUPPLY | Battery pack or external AC adaptor |
| PRICE | 75C: $995 - 75D: $1095 |
详解编辑本段回目录
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By 1982, Hewlett-Packard had made dozens of calculators, even programmable calculators, but the HP-75C is their first handheld portable computer. It's not their first computer though, that would be the HP-85 from 1980, two years earlier.
There is no built-in permanent data storage, but small magnetic cards can be used to load and save data. On the lower right face of the 75C is the card reader - just a slot where the tiny card is manually inserted and pulled out the right side by the user.
On the front are three expansion slots for tiny RAM or ROM cartridges to be inserted - additional user memory or applications can be added quickly and easily. The "C" in HP-75C is for "continuous memory" - it can access 120K total memory.
Here is another HP-75, but disguised as the "AT&T Information Systems" computer, resting in the HP-82718A expansion pod. The pod (originally $875) has 64K additional system memory, a 300 baud modem, and software to support a light-pen (there is a light-pen port on the back of the computer).
Because of the light-pen option, this is not an HP-75C, it's an HP-75D (released in February 1984 for $1095).
相关链接编辑本段回目录
参考文献编辑本段回目录
http://oldcomputers.net/hp75.html
http://www.old-computers.com/MUSEUM/computer.asp?st=1&c=640
