Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

ROM

IEC

IEC read-only memory (ROM)

A ROM is drawn with the ROM qualifier, usually followed by its organisation such as 256x8. Address inputs are grouped with a binary grouping bracket marked A, and data outputs carry an A label to show they deliver the addressed word. Enable inputs often control three-state outputs.

Drawing use

Schematic

Application

Logic & signals

Reference family

IEC / Manufacturer

Form evidence

Rectangular element with ROM qualifier, address grouping and A-dependent outputs. 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.

A distinction that matters

RAM adds write inputs; ROM outputs only.

Full referenceAdd to legend

RAM

IEC

IEC random-access memory (RAM)

A RAM symbol carries the RAM qualifier and organisation. Address inputs form an A group; a write input is labelled with control dependency, and data inputs are labelled A plus the control number and D, meaning data is written to the addressed word when the control is active. Data outputs are labelled A.

Drawing use

Schematic

Application

Logic & signals

Reference family

IEC / Manufacturer

Form evidence

Rectangular element with RAM qualifier, address grouping, write control and A-dependent data. 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.

A distinction that matters

ROM has no write inputs; FIFO memory has no address inputs.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.