With the PC-1251, Sharp started off their product range of really tiny pocket computers. It was the third original design after the PC-121x and PC-1500 series.
Contrary to its predecessors, it was really pocket sized, measuring only 135 x 70 x 9.5 mm. Nevertheless, it featured a 24 character display, and with 4 KB RAM it even outclassed the PC-1500 basic version. The major drawback of the new design was that the tiny keys are only compatible with pointed fingers.
The PC-1251 was based on a new 8-bit CMOS micro processor, the SC61860, which was mounted on the main PCB together with the display driver chip SC43536. On an additional small PCB, 24 KB ROM (LH532917) and 4 KB RAM (two HM6116 2k x 8 chips) were located. A new feature was the so-called "reserve memory" which allowed to assign often used BASIC commands or functions to 18 of the alphanumeric keys.
Together with the PC-1251, the CE-125 thermal printer and micro cassette recorder unit was introduced. With integrated NiCd accumulators, it was fully mains independent and made the 1251 into a very compact mobile computing system. The CE-125 also featured an additional tape interface for external tape recorders.
The PC-1250 was the same machine as the PC-1251 but with only 2 KB of RAM.
Our machine with the original rigid case, CE-125 interface, manual and power supply were all kindly donated by John D'Arcy of Birmingham
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This exhibit has a reference ID of CH6313. Please quote this reference ID in any communication with the Centre for Computing History.