Elecraft K3S firmware `v2.00`

Elecraft · Released Jun 6, 2008 · First seen Sep 14, 2026

v2.00 is not the latest firmware for the Elecraft K3S: the current version is v5.67 (January 22, 2019). Go to v5.67

In short — summary by updatemystuff.com

Fixes CW speaker noise with headphones, adds transverter band outputs, defaults mic button functions to off.

Eliminates periodic speaker noise in CW mode when using headphones
BAND0-3 ACC jack outputs now enable transverter band control
Mic button functions default to OFF to avoid issues with incompatible microphones

Written from Elecraft's release notes, which are printed in full below.

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BAND DATA FOR TRANSVERTERS: The BAND0-3 outputs on the 15-pin ACC jack can now be used to control transverters as described in the Owners Manual (revision C, page 18-19). To enable this feature, set CONFIG: KIO3 to HF-TRN (which outputs band decode data for both HF and transverter bands) or TRN (transverter band data only). The default is NOR (HF band decodes only).
CW MODE SPEAKER ARTIFACT ELIMINATED: Some operators reported a periodic burst of noise coming from the speaker when headphones were used in CW mode. This has been corrected.
MIC BUTTON FUNCTIONS DEFAULT TO OFF: Theres now a menu entry for turning the mic up/down buttons on or off (CONFIG: MIC BTN). The default is OFF, which makes these buttons inactive. You should turn it ON only if you have a mic whose up/down buttons provide contact closures to ground, with no resistors in series or in parallel (such as a Kenwood MC-43). Some mics have internal resistors and are not compatible with the K3s up/down feature. If you try to use such a mic (by setting CONFIG: MIC BTN to ON), VFO A may scan continuously.

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