ZENITH DATA SYSTEMS
Z-157 MODEL 2/MODEL 3
| Processor | 8088 | 
| Processor Speed | 4.77MHz | 
| Chip Set | Unidentified | 
| Max. Onboard DRAM | 640KB | 
| Cache | None | 
| BIOS | Unidentified | 
| Dimensions | 254mm x 218mm | 
| I/O Options | Parallel port/keyboard slot | 
| NPU Options | 8087 | 
 
| CONNECTIONS | |
| Purpose | Location | 
| Propietary parallel port/keyboard slot | S1 | 
| USER CONFIGURABLE SETTINGS | |||
| Function | Switch | Position | |
| » | RAM parity checking enabled | SW1/2 | On | 
| RAM parity checking disabled | SW1/2 | Off | |
| » | RAM over 256KB on mother board | SW1/3 | On | 
| RAM over 256KB on external memory card | SW1/3 | Off | |
| » | Parallel port enabled | SW1/6 | On | 
| Parallel port disabled | SW1/6 | Off | |
| » | Floppy controller enabled | SW1/7 | On | 
| Floppy controller disabled | SW1/7 | Off | |
| DRAM CONFIGURATION | |||
| Size | Bank 0 | Bank 1 | Bank 2 | 
| 512KB | (9) 41256 | (9) 41256 | NONE | 
| 640KB | (9) 41256 | (9) 41256 | (9) 4164 | 
| BOOT CONFIGURATION | ||
| Setting | SW1/0 | SW1/1 | 
| MFM-150 Monitor RAM | Off | Off | 
| MFM-150 Monitor RAM | On | On | 
| Floppy disk | Off | On | 
| Hard Drive | On | Off | 
| MONITOR CONFIGURATION | ||
| Setting | SW1/4 | SW1/5 | 
| Monochrome | Off | Off | 
| CGA | On | Off | 
| EGA | On | On | 
| MISCELLANEOUS TECHNICAL NOTE | 
| Note: Position 1 on SW1 is unidentified. |