The MFJ-495 Memory Keyer is a full-featured memory keyer combining dual microprocessors and a nonvolatile EEPROM chip for a full featured, low cost, high reliability design. Unlike other keyers, it uses a
LCD display to set keyer functions and show the sending message. The MFJ-495 keys CW from a
paddle, a keyboard and a serial computer interface. All code parameters are changed with an easy to use
menu interface shown on the LCD display. The MFJ-495 has 32 message memories total over 8000
characters which can be loaded by paddle, keyboard or from a computer with a terminal program. The
MFJ-495 can repeat messages continuously, insert timed pauses within messages, insert an autoincrementing serial number, have messages call other messages or insert embedded commands into a
message. Commands also can be simply sent to the keyer in Morse code using your paddles, keyboard,
terminal program on your computer, or push-button switches on the unit.
The MFJ-495 has controls for volume and speed on the front of the unit. The paddle jack connects to any
iambic or single lever (dual contact) key paddle. The keyboard port allows use of an optional keyboard
for keyboard keying operation. The serial interface allows connection of most RS-232 compatible
computers. The MFJ-495 supports both Direct and Grid-Block outputs and has a port for an optional
remote control. Some of its features:
• 2-line by 16-character LCD display.
• Iambic keyer with dot and dash memories; automatic, semi-automatic or hand-key mode.
• 32 messages (four banks of eight messages each) total over 8000 characters.
• Messages may “call” other messages and contain programmed functions.
• Message editing capability.
• Input queue to store multiple message activation.
• Auto-incrementing contest serial number from 001 to 9999.
• Digital and linear analog speed control from 5 to 99 WPM (2:1-to-20:1 speed range ratio).
• Farnsworth mode with speed from 10 to 99 WPM.
• Ultra speed mode allows messages at speeds up to 990 WPM.
• Adjustable weight on code elements from 25% to 75% (constant or speed dependent).
• Adjustable sidetone frequency from 300 to 1000 Hz.
• Compensation for transmitter character shortening up to 25 ms.
• Keying output delay up to 20 ms to accommodate switching delay.
• Push-to-talk (PTT) hang time up to 10 seconds.
• Direct (positive) or grid-block (negative) keying.
• Carrier tune and adjustable pulse tune functions for transmitter adjustment.
• Timed pauses within messages and message loop capability for continuous replay.
• Message and keyer configuration saved without battery backup.
• Internal sidetone speaker with adjustable volume.
• Support for Qwerty and Dvorak keyboards with RepeatKey feature.
• 190 characters type-ahead keyboard buffer with buffer-full warning.
• Quad user mode supports four operators with different configuration settings.
• LCD Display: A 2-line by 16-character alphanumeric display. It displays the keyer’s various menus
and the code being sent.
• Menu Button: Time-sensitive and used to navigate through the various menus and to enter or exit
the setup menus.
• Function Buttons: The general purpose Function buttons F1 to F4 perform the operations displayed
on the LCD above each corresponding buttons. They also use to navigate through the setup menus as
well as to change the keyer settings within the setup menus. These buttons are also time-sensitive.
Note: The F1 to F4 on the MFJ-495 will be referred to as “button” and the F1 to F4 on the
keyboard will be referred to as “key” throughout this manual.
ON
OFF
POWER
• Volume Control: Used to adjust the sidetone audio volume to the internal speaker and Audio Out
jack. Turn the control clockwise to increase the volume and counter-clockwise to decrease the
volume.
• PWR LED: Illuminates when the power to the unit is on. It also blinks when the keyer is in
message program mode and command mode.
• Speed Control: Used to adjust the code speed in a 2:1-to-20:1 ratio within the range of 5 to 99
WPM. Turn the control clockwise to increase speed and counter-clockwise to decrease speed.
Whenever the speed is changed using the front panel Speed control, the LCD momentarily displays
the change for approximately two seconds so you can see exactly what speed you just changed to.
Also, the Speed main menu is shown momentarily after the power is turned on, and then changes to
the last-used main menu.
• Power Button: Used to turn the unit on and off. Press to turn power on; press again to turn power
off.
WARNING:Do not turn the power on and off rapidly, otherwise the memory (keyer
settings) would be corrupted and the unit will have to reset to factory defaults
to function properly.
• Power: Accepts a standard 2.1 × 5.5 mm coaxial plug with positive center and negative sleeve. This
unit requires 12 volts DC. An optional 500 mA power supply, the MFJ-1315, is available from MFJ
Enterprises, Inc. This unit requires a minimum of 50 mA at no volume and without using a keyboard
and a maximum of 300 mA at maximum volume into an 8-ohm audio load with a typical keyboard. It
may require more current depending on the keyboard used; typical keyboard uses about 100 mA.
WARNING:Do not apply voltages greater that 18 volts to this unit, or permanent damage
to the unit may result.
KEY
INPUT
REMOTE
GND
DASH
DOTF4F3F2F1
MENU
• Audio Out: A 3.5 mm stereo phone jack for connecting to an external speaker or headphones. This
jack accepts both stereo and mono plugs. When this jack is used, the internal speaker is disabled. An
optional external speaker, the MFJ-281, is available from MFJ Enterprises, Inc.
WARNING: To prevent suffering hearing damage when using headphones, turn the
Volume control to minimum before putting on the headphones and then
slowly adjust for a comfortable volume.
• PTT Output: An RCA jack providing connection for a PTT (push-to-talk) output that goes low
when active. This jack is an open-drain output; an external pull-up can be used if so desired. Use a
quality-shielded cable for connection to this jack.
• Keying Output: This unit supports both
positive and negative keyed radios. Use a
quality-shielded cable for connection to this
RCA jack. Consult your transmitter's manual
to determine if it uses direct (positive) or
grid-block (negative) keying.
Two jumpers JMP1 and JMP2 inside the unit
set the keying output to direct for positive
keyed radios (most solid-state radios) or to
JMP1 JMP2 Keying Output
D D Direct *
D G Invalid
G D Invalid
G G Grid Block
radios with tube finals). Set both jumpers to the “D” positions for direct keying or to the “G”
positions for grid-block keying. If it is set wrong, the transmitter will either not key at all or key
continuously. The factory default * is direct keying output.
• Manual Key: An RCA jack providing an input line for manually keyed devices, such as a straight
key or a computer interface. An internal jumper JMP3
configures this jack to accept active-low (for straight key)
or active-high (output from computer software) input.
Set this jumper to the “L” position for active-low input or
to the “H” position for active-high input. If it is set
wrong, the keyer will key continuously. The factory
default * is active-high.
JMP3 Manual Key
L Active Low
H Active High *
Table 2. Manual Key Jumper.
• Serial Port: Accepts a standard 9-pin serial plug for connecting the MFJ-495 to a computer for
ASCII file transfers or monitoring your sending on the computer screen. A 9-pin-to-9-pin serial cable
is needed. If your computer has a 25-pin serial port, use a 9-pin-to-25-pin adapter.
To communicate with the MFJ-495, use a terminal program on your computer that is capable of
transferring information in ASCII format. Configure the software for 1200 baud, 8 data bits, 1 stop
bit and no parity; set the flow control to Xon/Xoff.
• Keyboard: Accepts most standard AT style keyboards (XT keyboard does not work with the MFJ-
495). The MFJ-551 keyboard is guaranteed to be fully compatible with the keyer and available from
MFJ Enterprises, Inc.
Two jumpers JMP4 and JMP5 inside the unit
configure the keyboard operation. Jumper
JMP4 selects whether a Qwerty or Dvorak
keyboard is used (see Figures 3 and 4 on next
JMP4 Keyboard Layout
L Qwerty *
H Dvorak
page); place this jumper on the “L” position
for the Qwerty keyboard or on the “H”
position for the Dvorak keyboard. Jumper
JMP5 set the RepeatKey feature that selects
JMP5 RepeatKey
L Off *
H On
whether or not to repeat a key when it is held
down; place this jumper on the “L” position
Table 3. Keyboard Jumpers.
to disable RepeatKey or on the “H” position
to enable RepeatKey. The factory defaults * are Qwerty keyboard and RepeatKey off.
• Key Input: A ¼-inch stereo phone jack for connecting to a paddle. An iambic or single lever (dual
contact) paddle with a shielded cable should be used. When used with paddles, the dot wire should
be connected to the tip of the plug, the dash wire to the ring, and the ground wire to the shield.
• Remote Port: The last port on the back of the unit is for the optional remote control. The remote
control gives you remote access to the keyer menu if the main unit is out of reach. The remote has
the menu and function buttons as well as the paddles connections. The remote connector combines
both the remote functions and the paddle jack so that only one cable from the paddle to the keyer is
needed.
You may connect the MFJ-495 to a computer using the 9-pin DIN serial port on the back panel. If your
computer has a 25-pin serial port, you can use a 25-pin-to-9-pin adapter.
To use a computer with the MFJ-495, run a terminal program that will upload and download ASCII files,
and configure the terminal program to do so. Set the terminal program for 1200 baud, 8 data bits, one
stop bit and no parity; set the flow control to Xon/Xoff. If you see extraneous linefeeds on the computer
screen when receiving data from the MFJ-495, you may configure your software to strip out these extra
linefeeds.
During sending, the characters sent by the MFJ-495 are sent through the serial port, so you may use your
computer to monitor the transmitted copy. You may find this particularly convenient.
You also may upload and download text files between the MFJ-495 and your computer. For details on
this, see the discussion of “Uploading and Downloading Messages” on page 34.
The Memory Keyer is simple to operate. The Power button controls power to the unit. Start sending with
a paddle or keyboard. Adjust the volume and speed to your preference. If the speed is still too fast or too
slow, adjust the range of the Speed control using the Speed and Ratio commands.
All characters or code sent by the user are played on the sidetone speaker. This allows the user to hear
what he is keying, typing, or sending with a computer. Only when the keyer is used with a paddle is the
code sent as soon as it is keyed. When using a keyboard or keyer terminal, you may type ahead of the
code that is being transmitted. This allows you to enter words and phrases faster than the transmitted
code. This permits smoother code with less pauses because you can fix misspelled words and think of the
right phrase to use while your previous sentence is being sent.
When you are in command mode, memory save, or configuration mode, the code sent to the speaker is
not sent to the Keying Output or your radio. This keeps all erroneous code off of the air.
How to Use the Menu System
You may set up the MFJ-495 to perform any of its many functions by making the appropriate selections
from its menu system. This system consists of seven main menus and 22 setup menus. You make your
selections using the five buttons under the LCD display - Menu, F1/Previous ◄, F2/Next ►, F3/Down
▼, and F4/Up ▲. These buttons do the following:
• Menu - Scrolls through the main and setup menus when press briefly. To enter the setup menu, press
and hold this button for two seconds. To exit the setup menu, press and hold this button for two
seconds to go back to the main menu.
• F1/Previous - Selects the main menu command or the previous setup menu.
• F2/Next - Selects the main menu command or the next setup menu.
• F3/Down - Selects the main menu command or the previous item in a setup menu.
• F4/Up - Selects the main menu command or the next item in a setup menu.
The main menus are arranged in a "wrap-around" structure, so that momentarily pressing the Menu button
will bring up another main menu in a sequence. Figure 5 shows the sequence of the main menus. When
power is turned on, the main menu displayed is the one that was displayed when the unit was last turned
off.
COM DEC CXT PXT
[A] B C D
A [B] C D
A B [C] D
A B C [D]
SPEED
FARNSWORTH
WEIGHT
TONE
(Bank A)
(Bank B)
(Bank C)
(Bank D)
(Bank A)
(Bank B)
(Bank C)
(Bank D)
(Bank A)
(Bank B)
(Bank C)
(Bank D)
MENU
For 2 sec.
MENU
For 2 sec.
MENU
or
SETUP MENUS
PEED RATIO
VERALL SPEED
FARNSWORTH
CCW WEIGHT
CW WEIGHT
CHAR SPACE
WORD SPACE
EY COMPENSATION
KEY DELAY
PTT HANG TIME
TONE
SERIAL NUMBER
LEADING ZEROES
OTHER ZEROES
NINES
IAMBIC
REVERSE
PADDLE
MONITOR
OUTPUT
QUEUE
USER
Press
Press
Press
Press
Press
MENU
BUTTON
ACTION
to
navigate
menus.
Press + to select Bank A.
Press + to select Bank B.
Press + to select Bank C.
Press + to select Bank D.
Press + to select MSG1-MSG4 main menu.
Press + to select MSG5-MSG8 main menu.
MENU
MENU
MENU
MENU
MENUDIT
MENU
to go to
previous
menu.
1
2
3
4
DAH
to go to
next
menu.
to
decrease
setting.
to
increase
setting.
Figure 5. MFJ-495 Menu Flow and Button Action Chart.
The setup menus are also arranged in a "wrap-around" structure, so that pressing the Previous or Next
button will bring up another setup menu in a sequence. Also, momentarily pressing the Menu button will
bring up the next setup menu. Figure 5 shows the sequence of the setup menus. When entering the setup
menus, the setup menu displayed is the one that was last used.
To see how the setup menu system works, consider the following example.
EXAMPLE: To enter the setup menu, press and hold the Menu button for two seconds. If the
display shows that you are in the Overall Speed menu, pressing the Next button would put you in
the Farnsworth menu and pressing the Previous button would put you in the Speed Ratio menu.
Pressing the Down or Up button would lower or raise the overall code speed. Once you have
selected the speed you desire, you may leave the setup menu by pressing the Menu button again
for two seconds; or press Previous or Next button to go to another setup menu.
Once you have made your choices within the setup menus, they will be saved in non-volatile memory for
your next session.
The main menus allow you access to the commonly used functions. There are seven main menus
arranged in a “wrap-around” structure. When power on, keyer operation starts with the main menu that
was last used. The first two main menus (MSG1-MSG4 and MSG5-MSG8) let you play and save
messages. The next main menu allows you to enter command mode and tune modes directly as well as
decrement the serial number. The last four main menus give you easier access to the frequently adjusted
settings and display their current values. For the first three main menus, the four function buttons take on
different meanings and perform the operations displayed directly above each button. Within each main
menu, press the Menu button briefly to view the next main menu. Press and hold the Menu button for
two seconds to enter the setup menus (see below).
MSG1-MSG4 Buttons
This is the first message menu that consists of four messages buttons, where the digit (1-4) is the message
number and the letter (A-D) is the current memory bank. For example, [1A] is message number 1 of bank
A. To play a message, press and release the corresponding message button. To save a message, press and
hold a message button for two seconds until the keyer responds with “GO” (dah-dah-dit dah-dah-dah).
You may then key in a message using the paddle, keyboard or terminal. Refer to “The Memory” section
on page 36 for explanation of the MFJ-495’s message memory.
MSG5-MSG8 Buttons
This is the second message menu that consists of another four messages buttons, where the digit (5-8) is
the message number and the letter (A-D) is the current memory bank. For example, [8D] is message
number 8 of bank D. To play a message, press and release the corresponding message button. To save a
message, press and hold a message button for two seconds until the keyer responds with “GO” (dah-dahdit dah-dah-dah). You may then key in a message using the paddle, keyboard or terminal. Refer to “The
Memory” section on page 36 for explanation of the MFJ-495’s message memory.
Command [COM] Button
Use to enter the command mode and the keyer will respond with “CO” (dah-di-dah-dit dah-dah-dah).
When a valid command is entered, the keyer will respond with “R” (di-dah-dit) when appropriate. If an
invalid command is entered, it will respond with an error character (di-di-di-di-di-di-di-dit). See the “The
Paddle” section on page 16 for more details on setup commands.
Decrement [DEC] Button
Use to decrement the serial number by one, effectively canceling the automatic increment applied when
last played from a message. The decrement function accommodates re-sending the last serial number, as
might be needed when a repeat of a contest exchange is requested, or canceling the exchange with a
station that proved to be a “dupe”. The unit will echo a "D" (dah-di-dit) for every number that is
decrement. Decrement serial number 0001 rolls over to 9999, because the number 0000 is not used.
Carrier Tune [CXT] Button
Use to engage the carrier tune mode. The keyer will key continuously to tune your station. Press any
button, paddle or key to exit.
Pulse Tune [PXT] Button
Use to engage the pulse tune mode. The keyer will send a continuous string of pulses to tune your
station. The rate (speed of 50 to 99 WPM) and the duty cycle (weight of 1% to 35%) of the pulses can be
adjusted with the function buttons. Press F1 button to decrease speed and F2 button to increase speed.
Press F3 button to decrease weight and F4 button to increase weight. Press Menu button, either paddle or
the ESC key to exit.
Speed
This menu is placed in the main menus to allow easier access to change the overall speed for the current
position of the Speed control in the range of 5 to 99 WPM. The speed shown on the display corresponds
to the current position of the Speed control. When
SPEED is displayed, press the Down button will
decrease the overall sending speed and the Up button will increase it. Note that setting the overall speed
higher than or equal to the Farnsworth speed will disable Farnsworth spacing.
Whenever the speed is changed using the front panel Speed control, the LCD momentarily displays the
change for approximately two seconds so you can see exactly what speed you just changed to. Also, the
Speed main menu is shown momentarily after the power is turned on, and then changes to the last-used
main menu.
Farnsworth
This menu is placed in the main menus to allow easier access to change the Farnsworth speed in the range
of 10 to 99 WPM. When
FARNSWORTH is displayed, press the Down button will decrease the
Farnsworth speed and the Up button will increase it. The Farnsworth speed must be higher than the
overall speed. To turn Farnsworth off, reduce the Farnsworth speed to the same speed as the overall
speed.
Weight
This menu is placed in the main menu to allow easier access to change the weight of code elements in the
range of 25% to 75%. Weight is the duty cycle of a continuous string of dots, which is 50% for perfect
code. The weight shown on the display corresponds to the current position of the Speed control. When
WEIGHT is displayed, press the Down button will decrease the code weight and the Up button will
increase it. Notice that adjusting the weight here changes both the CCW Weight and CW Weight to the
same percentage, resulting in a constant code weight. A higher weight produces a heavier sound, and a
lower weight causes characters to sound lighter. Once set, weight remains constant and independent of
the speed. For variable weight that adjusts with the speed, use the CCW Weight and CW Weight setup
menus (see below).
Tone
This menu is placed in the main menu to allow easier access to change the audio frequency of the
sidetone in the range of 305 to 1006 Hz. When
TONE is displayed, press the Down button will decrease
the sidetone frequency and the Up button will increase it. Most people prefer 700 to 800 Hz sidetone.
Changing Memory Banks
To change the memory banks from any main menu, press and hold the Menu button and then within two
seconds press the F1 button for bank A, F2 button for bank B, F3 button for bank C, or F4 button for bank
D. The keyer will respond with “BA”, “BB”, “BC” or “BD” for the selected bank. Each memory bank
has eight message memories (see “The Memory” section on page 36 for more details).
Miscellaneous
A shortcut to the message menus from any main menu is to press and hold the Menu button and then
within two seconds press the Dit paddle to select the MSG1-MSG4 menu or press the Dah paddle to
select the MSG5-MSG8 menu.
. Notice there is only one set of “[” and “]” that indicates the current memory bank. To change to
[D]
COM DEC CXT PXT will change to [A] [B] [C]
another memory bank during playback, press the corresponding function button.
Setup Menus
The setup menus allow you to set up how the MFJ-495 works and behaviors. There are 22 setup menus
arranged in a “wrap-around” structure. To access these setup menus, press and hold the Menu button for
two seconds. The setup menu that will display is the one that was last used. When finishing, press and
hold the Menu button for two seconds to go back to the main menus for normal operation. The LED will
blink to indicate that you are in the setup menus. The Keying Output and PTT Output are also disabled.
Within each setup menu:
• Press the Menu button briefly to view the next setup menu; press and hold the Menu button for two
seconds to exit the setup menu and go back to the main menu.
• Press the Next button to view the next setup menu; press the Previous button to view the previous
setup menu.
• Press the Up or Down button to change the setting for that setup menu.
Speed Ratio
The Speed Ratio menu is used to set the speed ratio of the Speed control in the range of 2:1 to 20:1. This
ratio is the speed at the full clockwise position to that at the full counter-clockwise position. With
minimum overall speed of 5 WPM, a ratio of 20:1 will cover the entire speed range of 5 to 99 WPM.
Default speed ratio is 3:1 making the Speed control less sensitive and easier to adjust the code speed.
Overall Speed
The Overall Speed menu allows you to set the code speed for the current position of the Speed control in
the range of 5 to 99 words per minute (WPM). There are three numbers on line two of the display. The
first number is the speed at the full counter-clockwise position of the Speed control; the second number
enclosed within “[” and “]” is the speed corresponding to the current position of the Speed control; and
the last number is the speed at the full clockwise position of the Speed control. You can also adjust the
Speed control to where you want it to match the speed shown on the display.
By "overall" speed, we mean the speed at which the words are sent. A "word" is defined as 50 units of
time, and the word "PARIS" is exactly 50 units in length. Therefore, if "PARIS" is sent 13 times in one
minute, the sending speed is 13 WPM. Standard Morse code timing defines a dit as one unit of time and a
dah as three units of time. Within each character, there is one unit between elements (dits and dahs).
Three units separate characters and seven units separate words. Farnsworth spacing (see below) will
increase the amount of time between characters and words. Note that setting the overall speed greater
than or equal to the Farnsworth speed will disable Farnsworth spacing.
Farnsworth
The Farnsworth menu allows you to disable or enable Farnsworth mode and set the Farnsworth speed
(character speed) in the range of 10 to 99 WPM. When Farnsworth mode is enabled, characters (dots,
dashes, and intra-character spaces) are sent at the Farnsworth speed, but the spacing between characters
and words is increased to produce a slower overall speed. This technique is useful for helping the novice
learn the sounds of the code characters and avoid the tendency of counting individual dots and dashes.
The Farnsworth speed is always higher than the overall speed. As a result, Farnsworth mode (if enabled)
is automatically disabled when the overall speed is changed to one that is greater than or equal to the
current Farnsworth speed. Also, Farnsworth speed cannot be enabled when the overall speed is at its
maximum of 99 WPM.
CCW Weight
The CCW Weight menu is used to set the code weight at the counter-clockwise (CCW) position of the
Speed control. There are three numbers on line two of the display. The first number enclosed within “[“
and “]” is the CCW weight; the second number is the weight corresponding to the current position of the
Speed control; and the last number is the CW weight. Constant weighting is achieved when all three
numbers are the same.
Weight is the duty cycle of a continuous string of dots, where 50% for perfect code. A higher weight
produces a heavier sound and a lower weight causes characters to sound lighter. Weight can be set to
remain constant and independent of speed, or it can be set to vary with the code speed.
CW Weight
The CW Weight menu is used to set the code weight at the clockwise (CW) position of the Speed control.
There are three numbers on line two of the display. The first number is the CCW weight; the second
number is the weight corresponding to the current position of the Speed control; and the last number
enclosed within “[“ and “]” is the CW weight. Constant weighting is achieved when all three numbers are
the same.
Weight is the duty cycle of a continuous string of dots, where 50% for perfect code. A higher weight
produces a heavier sound and a lower weight causes characters to sound lighter. Weight can be set to
remain constant and independent of speed, or it can be set to vary with the code speed.
25% Weight
50% Weight
75% Weight
Figure 6. Code Weight.
Character Space
The Character Space menu is used to increase the character space (normally three units) up to 12 units
long. There are two numbers on line two of the display; the number enclosed within “[“ and “]” is the
character spacing and the other number is the word spacing. Note the character space is always at least
four units shorter than the word space. So you might have to increase the word spacing before adjusting
the character space.
Word Space
The Word Space menu is used to increase the word space (normally seven units) up to 16 units long.
There are two numbers on line two of the display; the number enclosed within “[“ and “]” is the word