4025
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The Tektronix 4025 is a raster graphics terminal. The 4024 is a text-only variant. please expand
Key Specifications
| CRT | 11" diagonal (7.5"x5.6" / 19.1x14.2 cm²), green P39 phosphor |
|---|---|
| Graphics resolution | 640 × 480 pixels |
| Alphanumeric format | 35 lines, 74 characters per line, 5×7 dot matrix |
| Character set | 63 characters |
| Vector draw time | 3.6 ± 0.2 ms |
| Baud rate | 75 to 4800 baud |
| Input power | 110/240 VAC, 50 to 440 Hz, 105 Watts |
Links
- Tekscope Vol. 10 No. 1, Feb 1978 discusses the 4025
- Tektronix 4025 @ terminals-wiki
- A Granite 4025 @ vintagetek.org
Documents Referencing 4025
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| Tekniques vol.2 no.6.pdf | Article | 4051 Controls Real Time System for Micro-Mouse Contest | Miki Tokola | 1978 | 4051 • 4924 • 4025 |
| Tekscope 1978 V10 N1.pdf | Article | The Virtual Bit Map Brings High Resolution Graphics to the Alphanumerics Terminal User | Stan Davis | 1978 | 4025 |
| Tekscope 1978 V10 N1.pdf | Article | A New Concept in Data Representation: The Complete Integration of Graphics and Alphanumerics | Jack Liskear | 1978 | 4025 |
Internals
The 4024/4025 use an Intel 8080A CPU. Later it was upgraded to an 8085 to increase speed.
The original 8080 firmware was stored in mask-programmed ROMs. Firmware updates didn't change the ROMs; instead, off to the side there was a "patch ROM" (a small EPROM) and a "patch FPLA". The FPLA was an address decoder, which triggered when the CPU executed the first instruction in the range to be modified, and fed the CPU a jump instruction to the patch ROM, where the updated code would do its thing and jump back to the mask ROM. Update capacity was limited by how many addresses you could cram into the FPLA and how much code into the EPROM. The 8085 CPU board was designed after EPROMs became cost-effective to store the entire firmware.
