IBM 5150 Technical Reference page 293

square wave. An alternating or pulsating current or voltage whose
wave shape is square.
square wave generator. A signal generator delivering an output
signal having a square waveform.
SS. Start-stop.
start bit.
(1)
A signal to a receiving mechanism to get ready to
receive data or perform a function. (2) In a start-stop system, a
signal preceding a character or block that prepares the receiving
device for the reception of the code elements.
start-of-text (STX). A transmission control character that
precedes a text and may be used to terminate the message
heading.
start-stop system. A data transmission system in which each
character is preceded by a start bit and is followed by a stop bit.
start-stop (SS) transmission. (1) Asynchronous transmission such
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that a group of signals representing a character is preceded by a
start bit and followed by a stop bit. (2) Asynchronous
transmission in which a group of bits is preceded by a start bit
that prepares the receiving mechanism for the reception and
registration of a character and is followed by at least one stop bit
that enables the receiving mechanism to come to an idle condition
pending the reception of the next character.
static memory. RAM using flip-flops as the memory elements.
Data is retained as long as power is applied to the flip-flops.
Contrast with dynamic memory.
stop bit.
(1)
A signal to a receiving mechanism to wait for the
next signal. (2) In a start-stop system, a signal following a
character or block that prepares the receiving device for the
reception of a subsequent character or block.
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storage.
(1)
A storage device. (2) A device, or part of a device,
that can retain data. (3) The retention of data in a storage device.
(4) The placement of data into a storage device.
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