Epson PX-4
![]() The Epson PX-4 | |
Also known as | HC-40 HX-40 PX4-B HC-41 HX-41 |
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Manufacturer | Seiko Epson |
Type | portable computer |
Release date | 1985 |
Operating system | CP/M |
CPU | Zilog Z80 |
Memory | 64K RAM |
Storage | OptionalMicrocassettecartridge |
Display | 40×8 characters |
Graphics | 240×64 pixels |
Power | Rechargeable nickel-cadmium battery pack (Epson RB 105), 4xAA batteries, or a 6V 600mA DC power supply |
Predecessor | Epson HX-20 |
TheEpson PX-4(HC-40 or HX-40) is a portableCP/Mbased computer introduced in 1985. The screen was 40×8 characters physical, but 80×25 or 40×50 virtual,[1]making it almost compatible with theEpson PX-8 Geneva.It could be operated from a Nickel-Cadium battery pack (Epson RB 105), 4xAA batteries, or a 6V 600mA DC power supply.
It was targeted as successor of theEpson HX-20portable,[2]which was very popular with field engineers.
Another feature of the PX-4 was its high modularity. Inheriting the ROM capsules from theEpson PX-8 Geneva,it added a cartridge bay (similar but incompatible with theEpson HX-20), for which Epson offered several printers, micro-cassette drive, modem, EPROM writer, DMM (Digital Multimeter Module), RAM and ROM cartridges.[3]Third parties could make custom cartridges. The modem, EPROM writer and DMM needed user programs. The system allowed for BIOS extensions (User BIOS). Other features were the SerialandRS232 port, barcode reader interface like with theEpson PX-8 Geneva.New were a cassette port andparallel printer port.
The keyboard was also easily replaceable, allowing country specific layouts but also custom layouts, like the 'item keyboard' turning the PX-4 into a cash register. This trend was taken further by theEpson PX-16for which even 'item keyboards' with touch screens were available.
Internal RAM was 64K, of which a part could be reserved as RAM disk. An External RAM disk could be attached, creating a 120K RAM disk, leaving internal RAM as user BIOS and workspace.
The PX-4+ was an improved version which had the External RAM disk integrated (HX-45 in the US, HC-45 in Japan).
References
[edit]- ^PX-4 BASIC REFERENCE MANUAL, WIDTH command
- ^"Epson PX-4 - Computer - Computing History".computinghistory.org.uk.Retrieved2 November2021.
- ^PX-4 OPERATING MANUAL
- Literature
- PX-4 / HX-40 Operating System Reference Manual,EPSON, 1985. Y20699101600
- PX-4 DISK UTILITIES OPERATING MANUAL,EPSON, 1984. H8592003-0 / Y322990003
- PX-4 BASIC REFERENCE MANUAL,EPSON, 1985. Y200599100601
- PX-4 OPERATING MANUALEPSON 1985. H8592005-1 / Y205991005
External links
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