Remember dBm
Full name: Decibels referenced to one milliwatt
Memory aid: dB plus m means a milliwatt reference.
dBm is an absolute level; dB alone commonly expresses a ratio.
Study area: Wi-Fi & radio · Batch 6
Relevant study for: CompTIA A+ Core 1 220-1201 · CompTIA Network+ N10-009 · Cisco CCNA 200-301 · ISC2 CISSP 2024 outline
Practice with exam flashcards →Networking & Connectivity / Knowledge library
dBm — Decibels referenced to one milliwatt
Expresses an absolute power level relative to one milliwatt.
Why learn dBm — Decibels referenced to one milliwatt?
Expresses an absolute power level relative to one milliwatt.
Where it came from
dBm is an absolute level; dB alone commonly expresses a ratio.
- Memory aid (a learning cue, not the expansion): dB plus m means a milliwatt reference.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Without looking, expand dBm: Decibels referenced to one milliwatt.
- Recall this memory aid: dB plus m means a milliwatt reference.
- Explain the practical use: Expresses an absolute power level relative to one milliwatt.
- Explain this distinction: dBm is an absolute level; dB alone commonly expresses a ratio.
- Identify dBm in a device specification, architecture diagram, or system inventory.
Documentation and sources
- Wi-Fi Alliance technology (www.wi-fi.org)
- IEEE wireless LAN working group (www.ieee802.org)