The MFJ-407C uses a reliable Keyer-IC to make sending perfect code easier.
CONTROL FUNCTIONS
1. The PWR switch turns the unit ON and OFF.
2. The SPEED CONTROL varies code speed from 5 to over 60 WPM.
3. The WEIGHT CONTROL varies the code weight. The standard dot-dash-space ratio (counter-
clockwise) is 1:3:1. This control is turned clockwise to increase dot and dash lengths.
4. SEMI-AUTO allows semi-automatic "bug" and manual operations. The keyer generates dots au-
tomatically when a squeeze or single lever key is used. Dashes are manually made. The keyer
is completely manual when a straight key is used.
5. The TONE CONTROL sets the desired sidetone pitch.
6. The TUNE SWITCH continuously keys the transmitter for tuning.
7. The VOLUME CONTROL adjusts the loudness of the sidetone from the internal speaker.
8. IAMBIC A/B SELECT is inside the unit. A strap allows the user to choose between IAMBIC Type
"A" or Type "B".
Type "A" does NOT produce a following alternate element when a squeeze is released during a dot
or dash. Type "B" does produce a following alternate element after squeeze release. For example,
in Type "A", a squeeze release during the "dah" in the letter A will produce "dit dah" (A). In Type
"B", squeeze release during the "dah" in the letter A will produce "dit dah dit" (R).
Note: Power must be off when changing the strap setting.
INSTALLATION
1. A 9 V transistor battery may be installed by removing the two screws on the side of the box.
2. An optional AC ADAPTER (12 VDC), the MFJ-1312B may also be used. One end of the
ADAPTER should be plugged into the subminiature jack on one the rear panel and the other
end should be plugged into a 110 V (230 V) outlet. Batteries are automatically disconnected
when the external power is used. An adapter with a 2.1 mm coaxial plug and a sleeve as
ground should be used.
3. A squeeze or single lever key can be used. Squeeze key allows IAMBIC operation. A 3.5 mm
stereo phono plug and a two-conductor shielded cable should be used. The two shields should
be tied together and connected to ground if separately shielded cables are used. The dot wire
should next be connected to the ring of the plug and the dash wire to the tip. The MFJ-407C
becomes a manual keyer when a straight key is used. The unit will safely key your transmitter
and eliminate the shock hazard of high voltage being present on the straight key.
Note: To use a straight key, first switch the keyer to the SEMI-AUTO mode. Again a 3.5 mm stereo
phono plug should be used because a mono plug will not work on a straight key on SEMI-AUTO
mode. Connect one wire to the tip of the plug and another wire to ground. The ring of the plug
should not used.
MFJ-407C DELUXE ELECTRONIC KEYER
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