Many portable computers from back in the day had one or more ‘Option ROM’ sockets. This allowed the user to add in new software in ROM by plugging in a chip. While some such ‘Option ROM’ sockets were normal IC sockets some used a special Molex socket which required a special chip carrier for the IC. To further complicate things some computers even wired the socket in a non-standard way.
These days we have modern FLASH based memory that can hold a lot more bits than we could have dreamed of in the 1980s. Add in a rotary DIP switch and a bit of creative design and you have yourself a ‘Dial-A-ROM’ which can contain up to 16 ROM images for your computer. You rotate the DIP switch to the ROM you want to run, type in the commands to ‘install’ the ROM and your set. When you want to switch to a different ROM, type in the commands to ‘uninstall’ the ROM, rotate the switch, etc. You can only 'run' one ROM at a time from a Dial-A-ROM.
The Dial-A-ROM provides a simple and cost effective means to have multiple programs in ROM available eon your computer. It comes preloaded with the most popular programs that are publicly available online. There is even a programming adapter which will allow you to program ROM banks to your liking using your EPROM programmer that is capable of programming the FLASH chip.
Versions available for: TRS-80 Model 100, TRS-80 Model 102, TRS-80 Model 200, NEC PC-8201a, Epson PX-8, Epson HX-20
See PDF in Downloads tab for list of preinstalled ROMs and instructions.
Downloads and Video
These ROMs which were publically available online come pre-installed. Click Here
This video shows the installation of a DAR on a TRS-80 Model 100 as well as adding a new ROM image.