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Friden 1162 Technology


Electronics

Friden 1162
Small-Scale Integration ICs using a combination of DTL and TTL chips by Texas Instruments. There are also three cutom MSI counter chips. The ICs in the example machine have date codes from 1969.

Architecture, Memory & Speed

The 1162 is essentially a re-implementation of the 3-counter Friden EC-132 using late 1960s small scale integration, with several custom-fabricated medium scale ICs to implement the counters that are the foundation of its logical architecture.

  • Digits are encoded as a single pulse within a defined time frame, the time of the pulse within the frame indicating the digit value. 16 such frames represent a register and the registers are constantly circulated over a single bit serial internal data bus.
  • Magnetostrictive delay line memory. The digit encoding and register circulation architecture is readily suited to the single-bit, serial character of delay line memory.
  • @@kHz master clock, @@mS pulse time, @@mS digit time, @@mS total delay line length.

Construction

Construction is very similar to the EC-130 and in many respects the 1162 is like a scaled-down version of the EC-130. The external metalwork patterns and the internal chassis design is almost identical although the CRT display has been moved to the left hand side of the machine, for no obvious reason.

The keyboard is still mechanically encoded with magnetic reeds as the switching elements. The 1162 keyboard is another intricate design and is quite different to the EC-130, using a series of rotating rods rather than sliding plates. The 1162 keyboard retains the mechanical lock which holds a key in the down position until it is released by a signal from the electronic logic. The keystroke feel is rather direct and mechanical, quite unlike the feel of the 130 series.

The electronic layout is very similar to the EC-130 series with the power supplies located in a compartment with the display tube and the logic located in a separate compartment. Four boards (the same as the EC-130 series) hold all of the logic and plug into a circuit board backplane. Like the EC-130, the edge connectors have a different pattern for each board, to prevent mislocating a board.