Voiceband represents the audio frequency spectrum from 300 Hz to 3400 Hz. Telephone engineers established this 3.1 kHz band as the minimum range required to make human speech intelligible while maximizing the number of channels that could fit on a single trunk line. Legacy modems and fax machines modulate digital data specifically to fit within this narrow acoustic window.
You can't push high-fidelity audio over that circuit because it's filtered down to standard voiceband.
Also heard as
- voice frequency
- VF
Related terms
POTS
Plain old telephone service is the traditional analog voice transmission network using copper wires.
PSTN
The global infrastructure of circuit-switched telephone networks operated by national and regional carriers.
Frequency
The number of cycles a radio wave or alternating current completes per second.
Band
A specific, contiguous range of frequencies in the electromagnetic spectrum allocated for a particular use.