# IEC interconnection dependency (Z)

Canonical URL: https://eloragrid.ai/symbols/iec-interconnection-dependency-z
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: Zm
Drawing use: Schematic
Reference families: IEC, Manufacturer

## Symbol convention

Convention: IEC
Form: Output or internal output labelled Zm with affected terminals labelled m
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.

Dependency label Zm showing an internal connection from one point of a symbol to every terminal labelled m.

## In plain English

### What does IEC interconnection dependency (Z) mean?

Z dependency states that the affecting input or output is internally connected to every input or output labelled with the same number, which then takes its logic state. It lets a symbol show internal wiring without drawing it, for example an internal output that drives several internal inputs.

### A simple example

On device symbols, Z dependency often explains why an output appears to have the same state as an internal signal or why a pin also acts on another function. Drafters reproducing such symbols should keep the labels together.

### What the drawings help you do

Z dependency indicates logic state transfer only. It does not imply the connection is externally accessible or measurable.

### This particular reference

Dependency label Zm showing an internal connection from one point of a symbol to every terminal labelled m. X (transmission) dependency describes a bidirectional switch path controlled by the affecting input; Z is a fixed logical connection.

### Terms

- Terminal: An identified point where a conductor connects.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf)


## What it represents

Z dependency states that the affecting input or output is internally connected to every input or output labelled with the same number, which then takes its logic state. It lets a symbol show internal wiring without drawing it, for example an internal output that drives several internal inputs.
On device symbols, Z dependency often explains why an output appears to have the same state as an internal signal or why a pin also acts on another function. Drafters reproducing such symbols should keep the labels together.
Z dependency indicates logic state transfer only. It does not imply the connection is externally accessible or measurable.

## How to read it

- Trace each Zm to every terminal labelled m.
- Z labels describe internal connections, not external wiring.

## Information to show or reference

- Label the source as Zm.
- Mark each connected terminal with m.
- Do not use Z labels to stand in for external wiring.

## Important distinction

X (transmission) dependency describes a bidirectional switch path controlled by the affecting input; Z is a fixed logical connection.

## Facts

- Meaning: Internal logic connection
- Typical use: Internal outputs feeding several functions
- Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic

## Public references

- [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf) — Texas Instruments. Z (interconnection) dependency description.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.