MFJ 1204 User manual

INSTRUCTION MANUAL
CAUTION: Read All Instructions Before Operating Equipment
MFJ ENTERPRISES, INC.
300 Industrial Park Road
Starkville, MS 39759 USA
Tel: [phone] Fax: [phone]
COPYRIGHT 2016 MF J ENTERPRISES, INC.
Model MFJ-1204
VERSION 1A
USB Radio Interface

Introduction: The MFJ-1204 puts you in touch with Ham Radio's digital
revolution without complex wiring or setup procedures. In fact, the MFJ-1204 is
easier to set up and use than any other USB-interface on the market. All you
need is an existing radio, a computer, some free downloadable software, and
your MFJ-1204.
MFJ-1204 Features:
[ ] Full USB connectivity
[ ] Powered by USB port, no power adapter needed.
[ ] Dedicated on-board sound card
[ ] Quick plug-and-play Windows connectivity
[ ] Only two adjustable controls to operate
[ ] Works with all digital modes
[ ] Dozens of free downloadable programs available
[ ] Innovative PTT detector circuitry eliminates VOX delay
[ ] Uses widely available interface cables for most popular radios
[ ] Low cost, small size, light weight
[ ] Perfect for base station, portable operation, or "go-kit" use
Overview: You'll begin setup by looking up the jumper settings for your radio (in
the manual, on line, or with radio cable instructions). Then, you'll remove the
MFJ-1204 cover and install the jumpers as illustrated (it only takes a minute).
Note that you MUST install the jumpers first, before connecting the interface to
your computer and radio.
Once jumpers are installed, the interface's signal cable connects to any free USB
port on your computer to obtain power and establish a two-way signal path. Your
computer should be turned on and booted up before this connection is made. To
complete the setup, install the prescribed radio interface cable between the
Radio port (J-45 connector on rear panel) and the mating jack on your
transceiver. Step-by-step instructions are provided for set procedures.
The MFJ-1204 supports virtually every data and digital-voice mode in use today.
With the appropriate software downloads, you can transmit and receive
traditional modes such as CW, RTTY, SSTV, AMTOR, PSK31, and EchoLink.
Or, you can explore newer modes like MT-63, WINMOR, WSPR, and WSJT-X. If
your radio can pass the signal and your computer can run the downloaded
program, the MFJ-1204's built-in sound card and your PC will handle the rest!
MFJ offers patch cables to fit most popular radios, and these cables are also
interchangeable with cables manufactured by SignalLink-USB (and possibly
others). Just purchase the correct one for your transceiver, plug in, and go.

Setting Jumpers:
Setting jumpers is a "one-time" procedure that interconnects your particular radio
to the MFJ-1204. If possible, use the jumper wires provided (#24 solid or solder-
tinned wire works best). Avoid larger wires that could damage the pin cups.
These jumpers route ground, PTT, transmit audio and receive audio to the
appropriate wires in the interface cable. To set jumpers:
[ ] Remove the two phillips-head screws securing the MFJ-1204 cover.
[ ] Remove the cover and set it aside.
[ ] Locate the 16-pin IC socket directly in front of the J-45 jack.
[ ] Note the labeling on the pc board for each of the socket connections.
To reduce the possibility of error, we recommend drawing out the required
jumper routings ahead of time on the template provided below (extra templates
also provided in case you change radios at a later time).
Note that this document is a preliminary manual for the MFJ-1204, so not all
jumper routings have been complied at this time. However, some setups are
shown in the back and continually updated setups may be found on MFJ's
website and on the Tigertronics Signalink site (jumper settings and interface
cables are interchangeable). Settings may also be provided on instruction sheets
that come with pre-wired interface cables.
To begin jumper setup:
[ ] Draw in the jumper settings for your particular radio.
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
Radio____________
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
Radio____________
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
Radio____________
[ ] Following your diagram, carefully install the jumpers at IC1.
[ ] Double check your installation to ensure it is correct.
[ ] Reinstall and secure the MFJ-1204 cover.

If making a cable for an unlisted radio, refer to its operating manual to determine
the appropriate jack and pin-out configuration to use.
Connecting to Your Computer
Important Note: Do not connect the MFJ-1204 to your computer until the
prescribed set of jumper wires have been installed, the computer is turned on,
and its operating system has fully booted up. Also, close any applications that
are open and running before plugging in the interface.
When you plug in the USB interface cable, the computer will signal that one or
more new devices have been connected. The interface sound card will then
automatically begin loading the following drivers:
USB Composite Device
USB PnP Sound Device
USB Human Interface Device
Installation typically takes less than a minute to complete. After the drivers have
loaded, select Restart and reboot you pc before continuing.
Important Warning: If you don't initiate a Restart before continuing, some
Windows machines may become unresponsive. Also, note that driver installation
is a one-time event for each USB port used. If you change USB ports, the
soundcard will repeat the setup sequence and you'll need to Restart again.
Selecting a Download Program: Literally dozens of downloadable shareware
communication programs are available for running a wide range of digital modes.
Many are quite inclusive, offering a selection of several modes -- and some may
work better for you than others. While MFJ doesn't recommend any particular
choice as the best to try, HamScope is well established, popular, and covers
several communication modes.
Selecting the USB Soundcard: Most communication programs will require you
to select a sound card as part of the setup procedure. Select USB Sound. This
choice directs your computer to access the sound card built into the interface unit
rather than the resident card installed in your computer.
Receive Audio Level: The interface's receive audio control is fairly uncritical and
relatively easy to set. When copying signals off-air, simply adjust it for the most
reliable on-screen display of incoming signals. If your receiver has built-in audio
EQ, we recommend setting it for flat response (±0 dB).
Be sure to leave the Transmit audio level at minimum (fully CCW) and don't
attempt to transmit while setting up the receive control.

Transmit Audio Level: Make sure your transceiver is operating into a low-SWR
antenna or dummy load before proceeding. Most communication programs offer
a "tune" function to provide a reference tone for setting transmit levels (check the
program's documentation for tune-up specifics). When setting up, start with the
Transmit control at minimum and bring it up slowly to avoid overdriving. Your
signal must be as linear as possible when transmitting digital signals, so consider
the following tips:
[ ] In addition to RF output, always monitor ALC level and set the interface
Transmit level below the threshold of ALC action. The ALC meter should not
deflect during digital transmissions.
[ ] Be sure to turn off RF speech processing and/or audio compression. Also, if
the radio has built-in transmit EQ, set it up for flat frequency response (±0 dB).
[ ] Most transmitter PAs exhibit gain compression when approaching maximum
output. Limiting output to 70% of maximum or even less substantially improves
linearity while making negligible difference in received signal strength.
[ ] Never use the radio's Power Output control to set power (use the Transmit
control on the interface). Most radios utilize ALC voltage to reduce power and it
compromises linearity.
Finally, some digital modes such as RTTY require your transmitter to operate at
maximum output power for extended periods. Be sure to reduce output well
below maximum or provide supplemental cooling to avoid PA transistors from
overheating.
Jumper Setups: These jumper settings are prescribed for the listed HF
transceivers. The associated radio cables use the connectors indicated above
the pictorials.

ICOM:
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
Icom 728, 728, 735,738
746PRO, 751, 756Pro
761, 765, 775, 781
Icom 706
RJ-45 Mic
8-Pin RD Mic 6-Pin Din Port
Icom 706*, 746*, 7000*
7100, 7400
*(set menu 29 for 1200 baud)
ICOM, KENWOOD, TENTEC:
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
13 Pin DIN 5-Pin DIN
Icom 706, 718* 7000*, 7100*
7200, 7300, 7410, 9100
*(Turn Down Mic Gain)
13-Pin DIN
Kenwood TS-140, 450S,
850, 870, 950, 570D, 590S
990, 2000
TenTec Argo-V, Jupiter,
Omni-VII, Pegasis
YAESU:
GND
GND
GND
PTT
MIC
SPKR
IC1
8
7
6
5
4
3
2
1
NC
NC
6-Pin Mini-DIN Data Port
Yaesu FT-100, 817, 857, 897
950, 991, 1500M, 7100, 7800R,
7900R, 8100, 8500, 8800R, 8890R
FTDX-1200, 3000

Check with the MFJ or the SignaLink website for additional settings and
operating notes.
In Case Of Trouble:
[ ] No Power to Interface: Remove the interface cover. If the sound card is
plugged in and receiving power, the red LED on the sound card module will be
illuminated. If it is not illuminated, check USB connection at the computer.
[ ] Communication Program not Working: Confirm the USB sound card has
been selected. Also, use a scope or AC voltmeter to confirm receive audio path
is good between the radio and the jumper block.
[ ] No Transmit, won't key: Check PTT line from jumper block to transceiver
connector for continuity.
[ ] Low (or no) Output Power, Distorted Transmit Signal: Check microphone
line from jumper block to transceiver connector for continuity. If applicable, check
radio's mic gain setting. Also, check Transmit setting on interface.
[ ] Communication Program won't Load up or run properly: Confirm that the
download program is compatible with your current operating system.
If you are unable to resolve the problem, check the MFJ and SignaLink sites for
special settings or conditions that may apply to your particular radio. Also,
contact MFJ Technical Support at 662-323-0549 for assistance. Be sure to
document the exact nature of the problem so our technicians can provide the
most efficient response. You may also contact [email protected]
on line with a description of the difficulty.