The Apple II Plus was the second model of the Apple II series produced. It had a total of 48 KB of RAM, expandable to 64 KB by means of the language card, an expansion card that could be installed in the computer's slot 0. The Apple's 6502 microprocessor could support a maximum of 64 KB of memory, and a machine with 48 KB RAM reached this limit because of the additional 16 KB of read-only memory and I/O addresses. For this reason, the extra RAM in the language card was bank-switched over the machine's built-in ROM, allowing code loaded into the additional memory to be used as if it actually were ROM. Users could thus load Integer BASIC into the language card from disk and switch between the Integer and Applesoft dialects of BASIC with DOS 3.3's INT and FP commands just as if they had the BASIC ROM expansion card.
Introduced 1978 and discontinued in 1982. The price was US$1200