PARITY
Parity generator / checker
Computes a parity indication from the defined digital input word.
Schematic
IEC · 2k+1
IEC odd-parity element
Element marked 2k+1 that is active when an odd number of inputs are active, as used for parity.
In plain English
What does IEC odd-parity element mean?
The 2k+1 additional drawing mark means the output is active when an odd number of inputs are active. It is what a cascade of two-input exclusive-OR gates actually computes, and it is the correct IEC additional drawing mark for an odd-parity tree drawn as a single element.
A simple example
Drafters converting older drawings sometimes mark a multi-input parity tree as =1. That is wrong under the IEC meaning, because =1 requires exactly one active input. Replacing it with 2k+1 removes the ambiguity.
What the drawings help you do
The element does not indicate the number of data bits on its own; show the full input set or a grouped bus with its width.
This particular reference
Element marked 2k+1 that is active when an odd number of inputs are active, as used for parity. The =1 element gives the same result only for two inputs.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A) · SN74LS280 — odd/even parity generation and checking
IEC · Rectangular element with the 2k+1 general qualifier
Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
Schematic · 2k+1
What it represents
The 2k+1 qualifier means the output is active when an odd number of inputs are active. It is what a cascade of two-input exclusive-OR gates actually computes, and it is the correct IEC qualifier for an odd-parity tree drawn as a single element.
Drafters converting older drawings sometimes mark a multi-input parity tree as =1. That is wrong under the IEC meaning, because =1 requires exactly one active input. Replacing it with 2k+1 removes the ambiguity.
The element does not indicate the number of data bits on its own; show the full input set or a grouped bus with its width.
How to read it
- Do not read 2k+1 as exactly one active.
- Check whether the result is used as odd or even parity downstream.
Information to show or reference
- Use 2k+1 for multi-input parity trees.
- State the word width.
- Reference the parity convention used by the protocol or memory.
A distinction that matters
The =1 element gives the same result only for two inputs.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)
Defines 2k+1 and contrasts it with =1.
SN74LS280 — odd/even parity generation and checking
Manufacturer parity generator and checker documentation.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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