MFJ-452 CW Keyboard
Instruction Manual
1
MFJ-452 Super CW Keyboard
Features
♦
Includes eight independent 250-character message memories.
♦
150-character type-ahead buffer available with audible "buffer full" warning.
♦
Paddle jack makes MFJ-452 a keyboard-controlled iambic keyer. Iambic paddle, space bar, or single-
lever usable as straight keys.
♦
Embedded commands include auto-incrementing serial numbers, timed pauses up to 99 minutes 99
seconds, and message loops.
♦
Adjustable parameters vary code speed from 5 to 100 WPM and code weight from 5 to 95 %.
♦
Internal sidetone speaker with adjustable volume and frequency.
♦
Output tune mode has constant key to adjust tuners or antennas.
♦
LCD readout displays buffer contents and transmitted text.
♦
Practice operation using key-output disable and Farnsworth mode for random code generator.
Installation
The MFJ-452 is supplied with an IBM-AT compatible keyboard. The MFJ-452X package does not
include a keyboard. The unit is guaranteed to support the supplied keyboard but may be used with other
standard 101 key AT-style keyboards. However, the use of an AT-compatible keyboard from other
manufacturers may cause an increase in susceptibility to radio frequency interference. If using a
switchable keyboard, move the A-X switch on the back of the keyboard to the "A" position.
Using an XT
style keyboard or turning a switchable keyboard to "X" mode may damage both the keyboard and the
MFJ-452. This unit will function only with AT compatible keyboards.
Plug the keyboard into the 5 pin
DIN connector marked
KYBRD IN
on the MFJ-452.
The MFJ-452 Morse Keyboard requires a 12 Vdc 250 milliamp power supply. The power jack accepts a
2.1mm coaxial plug with the center conductor positive and shield ground. An optional dc supply, the
MFJ-1312B, is available from MFJ Enterprises. Connect your MFJ-1312B Power Adapter or compatible
dc supply into the jack marked
POWER
on the MFJ-452 back panel.
This unit supports both positive and negative keyed radios. Connect a standard shielded RCA cable
between your radio key input and the MFJ-452's key output. The MFJ-452 is set up for a
direct
or
positive keyed radio (most solid state radios). The unit can be adjusted for
grid block
or negative radios
(most radios with tube finals) by shorting the left most pair of pins on JMP1. JMP1 is located, with the
POWER switch toward you, to the right rear of the PC board.
Connect the paddle to the 3.5mm stereo phone jack with a shielded cable through the back of the unit.
Connect the dot wire of the paddle to the ring on the plug and the dash wire to the tip. The shield on the
plug should be attached to paddle ground. An external speaker can be connected to the speaker output on
the rear of the unit using the 3.5mm mono plug.
