Editing Commodore Plus/4 (section)

== Peripherals ==

The keyboard on the Plus/4 was different from the keyboards of previous Commodore machines and also its sibling the C16; this was due to cost saving measures resulting from the need to retool for Plus/4 production, while the C16 could use the existing C64 tooling due to an identical case design.

Peripheral compatibility with the C64 was inconsistent. The Plus/4's serial, user, and video ports were compatible with the C64, but the [[Commodore Datasette|Datasette]] port was changed, rendering previous units incompatible without third-party adapters that only became available later. This also posed a problem for the many third-party C64 printer interfaces that allowed one to connect a standard [[Centronics]] parallel printer to the Commodore serial port. Since most of these interfaces connected to the Datasette port to get +5 volts for power, they were incompatible with the Plus/4 unless the user modified the interface and risked voiding the warranty. For a computer intended to be used for [[Productivity software|productivity applications]], this was a heavy weakness. Additionally, with the Plus/4, Commodore abandoned the common [[Atari 2600|Atari]]-style [[joystick]] ports used on the C64, replacing them with a [[Proprietary hardware|proprietary]] [[Mini-DIN connector#8-pin|mini-DIN]] port that was said to be less prone to emit [[radio frequency|RF]] interference.

The Plus/4 does not support analog devices via the joyports like the C64 [[Computer mouse|mouse]], making programs with a [[Graphical user interface|GUI]] such as [[GEOS (8-bit operating system)|GEOS]] less friendly to use. However, there is an unfinished project that allows the use of a standard [[IBM PC compatible]] [[RS-232|serial]] mouse.<ref>{{cite web|url=http://my.opera.com/MMSZoli/albums/show.dml?id=11886182|title=Plus/4 - RS232 mouse project}}</ref>