The Psion Revo, launched in November 1999, is a PDA from Psion. It is the successor to the Psion Series 3 and a light version of Psion 5mx. It is software-compatible with the 5mx and has the same processor but is more lightweight and substantially smaller. In comparison with the Series 5/5mx, the Revo has a smaller screen and also lacks a flash-card slot and a backlight. The Psion Revo comes in two main variants, Psion Revo and Psion Revo Plus, having 8 and 16 MB of RAM respectively. It is powered by a 36 MHz ARM 710T microprocessor. Among other things, the hardware is equipped with a short-distance IrDA wireless infrared communication system and a touchscreen. Like its bigger counterpart Series 5mx, it comes with a small suite of office and communications programs built into the ROM chips. Other programs are user-installable by using a "dock" to send Revo programs from a PC. SONICblue produced a rebadged version of the Psion Revo Plus called the Diamond Mako, which they distributed in the United States and in Canada. Along with Enfour, Psion produced two versions of the Revo for the Chinese market called the 618C and 618S. An open-source project OpenPsion, formerly PsiLinux, aims to port Linux to the Psion Revo and other Psion PDAs. See the or the site of , which is an optimized version of OpenPsion for the Revo.
Conan
Shortly before the demise of Psion in the commercial PDA market work had begun on a successor to the Revo, a 3rd-generation PDA known by its codename of Conan. The Conan ran Epoc Release 6 and was to feature support for Bluetooth and a backlight, although the former wasn't functional in the development builds.
Battery
The Revo was notorious for battery and charging problems.. Unlike the Series 5mx, which used 2 user-replaceable AA batteries, the Revo is powered by 2 built-in rechargeable AAA 700 mAh NiMH batteries, which typically need to be replaced after about 3 years of service. After backing up all data, the batteries can be accessed by closing the unit, peeling off the Revo logo, moving the 2 small pins that are behind it, and lifting up the silver part of the casing. The batteries are wrapped in black tape, which can be removed starting from the left, taking care not to break the thermistor that it also encloses. It may not be possible to separate the batteries from their connectors without damaging the latter, which would then need to be replaced. Injury could result if separation is attempted with a blade. Replacement batteries must be taped in just as securely, otherwise resets could occur due to intermittent power loss. After replacing, the unit should be charged uninterrupted for at least 6 hours, so that the hardware can re-calibrate.
