IFSP (, ), or radial parallel interface, was a

parallel Parallel may refer to: Mathematics * Parallel (geometry), two lines in the Euclidean plane which never intersect * Parallel (operator), mathematical operation named after the composition of electrical resistance in parallel circuits Science a ...

interface Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Inter ...

similar to the

Centronics connector IEEE 1284, also known as the Centronics port, is a standard that defines bi-directional parallel communications between computers and other devices. It was originally developed in the 1970s by Centronics before its Institute of Electrical and ...

(IEEE 1284) but incompatible, as it had different signal polarities and handshake protocol. It was used in

printer Printer may refer to: Technology * Printer (publishing), a person * Printer (computing), a hardware device * Optical printer for motion picture films People * Nariman Printer (fl. c. 1940), Indian journalist and activist * James Printer (1640 ...

s and

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

s manufactured in

Comecon The Council for Mutual Economic Assistance, often abbreviated as Comecon ( ) or CMEA, was an economic organization from 1949 to 1991 under the leadership of the Soviet Union that comprised the countries of the Eastern Bloc#List of states, Easter ...

. All printer input signal lines were pulled up to +5V by a 220

Ohm Ohm (symbol Ω) is a unit of electrical resistance named after Georg Ohm. Ohm or OHM may also refer to: People * Georg Ohm (1789–1854), German physicist and namesake of the term ''ohm'' * Germán Ohm (born 1936), Mexican boxer * Jörg Ohm (1 ...

resistor A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active e ...

, and pulled down to ground by a 330

resistor. This allowed usage of longer cables compared to Centronics, but overloaded most usual Centronics adapters. Some devices allowed switching between IFSP and Centronics modes, i.e. Robotron 6319—6329 were manufactured with interchangeable interface modules, allowing usage of IFSP, IFSS and Centronics.

Signal description

See also