This ad is from a company called Data 20 Corporation and is promoting a series of cartridges for the VIC-20 and Commodore 64. They seem to be a combination of software and hardware upgrades.
The first product is the VIC 20 Video Pak which comes with Word Manager. The Video Pak allows the VIC-20 to display 40 or 80 columns instead of the stock 22 columns. The word processor worked with this 40 or 80 column mode. The advantage of an 80-column screen is that it gave you more of a WYSIWYG display since printers printed 80 columns. This cartridge also upgrades the memory to 12K.
The next product is the VIDEO PAK 80 for the Commodore 64. It added an 80 column monochrome display capability to the Commodore 64. By default, the Commodore 64 could only display 40 columns. It also included the free Word Manager word processing software, a terminal emulator mode, and a screen print function. I'm assuming the terminal emulator could be used with a modem to call BBSes or other online services.
The next product is the Z-80 Video Pak which added a Z-80 processor and CP/M capability to the Commodore 64 in addition to the 80 column display. CP/M was the standard for businesses before DOS took over so there was tons of software available for it. Obtaining CP/M software on disks formatted for the Commodore 64's 1541 disk drive could be difficult though.
Also included in this ad are more common items like a printer interface and memory expansion for the VIC-20. There is also an Expansion Chassis that lets you use up to four cartridges on the VIC-20.
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