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In telecommunication, a narrowband modem is a modem whose modulated output signal has an essential frequency spectrum that is limited to that which can be wholly contained within, and faithfully transmitted through, a voice channel with a nominal 4 kHz bandwidth.

Note: High frequency (HF) modems are limited to operation over a voice channel with a nominal 3 kHz bandwidth.

References

Public Domain This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).