Produced by International Computer and Tabulators Ltd. in London, it was introduced in 1964 barely six months after the launch of the IBM 360. It was a version of the Canadian FP6000 computer, supplemented with the ICT standard peripheral interface. The execution time for an addition instruction ranged from 2,5 microsec with the 1,1 microsec core store (for models 1906,1907) to 34 ?s with a 6 microsec core store (for the model 1901). These mainframe computers all used the same set of command meaning that a program written for one model could be used on bigger or smaller members of the series having the same options. The hardware of the machines was different, therefore, in order to implement the reverse compatibility, a program was needed that encapsulated the hardware and ensured further routines to support the hardware-specific commands. For the computers of the 1900 family, the word length was 24 bits, which could be used as four 6-bit characters. The early machines had a central memory installed which was the predecessor of the currently used Random Access Memory. The input and output units were designed of 80 column punch cards, a punch card reader and an 8 track punched paper tape.

In Hungary, KFKI was the first to buy an ICT 1905 type machine to replace the outdated vacuum tube URAL 1 working there. (KSH was given a machine with similar properties as well.) The machine was built with silicon transistors, had a 32 Kword (24 bit/word) capacity ferrite core main memory, and a 7 track magnetic tape memory and a 7,25 MB capacity changeable magnetic disc memory could be attached to it as well; for data entry it had an 8 track punched tape, and punched card input The outstanding machine already had an operating system, and it was delivered with compilers for the most known languages - ALGOL (ALGOrithmic Language), FORTRAN (FORmula TRANslator), COBOL (COmmon Business Oriented Language).

KFKI used the ICT machine creatively, they used it in a system with the TPA 1001 developed by them, that way both machines saw the other as its own peripheral device: ICT could operate the plotter of the TPA, and the TPA could operate the printer of the ICT. In addition the relatively slow reader of the TPA entered the data, which then it wrote into quickly to the main memory or the magnetic tape unit of the ICT.