MFJ MFJ-1270X User manual

MFJ ENTERPRISES, INC.
300 Industrial Park Road
Starkville, MS 39759 USA
Tel: [phone] Fax: [phone]
CAUTION: Read All Instructions Before Operating Equipment !
INSTRUCTION MANUAL
TNC-X Packet Controller
Model MFJ-1270X
V E RS ION 2A COP Y RI GHT 2013 M F J E N T ERP RI S E S , I NC.

MFJ-1270X Instruction Manual TNC-X Packet Contoller
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DISCLAIMER
Information in this manual is designed for user purposes only and is
not intended to supersede information contained in customer
regulations, technical manuals/documents, positional handbooks, or
other official publications. The copy of this manual provided to the
customer will not be updated to reflect current data.
Customers using this manual should report errors or omissions,
recommendations for improvements, or other comments to MF
Enterprises, 300 Industrial Park Road, Starkville, MS 39759. Phone:
[phone]; FAX: [phone]. Business hours: M-F 8-4:30 CST.

MFJ-1270X Instruction Manual TNC-X Packet Contoller
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Introduction................................................................................................4
Power Requirements .........................................................................5
Terminal Speed..................................................................................5
Setup If You Are Using USB..................................................................5
Setup If You Are Using the TNC’s Serial Port .......................................6
Back Connections..................................................................................6
Radio Setup...............................................................................................7
Radio Port Connections........................ Error! Bookmark not defined.
Cables ................................................................................................8
Radio Connection ..................................................................................8
Setup and Troubleshooting .......................................................................9
Receive Testing.....................................................................................9
Transmit Testing ................................................................................9
Can receive another node but can not get the node to respond. ......9
Can transmit but not receive the node. Can not hear a working node.
.........................................................................................................10
1270X seems to receive but the computer is not displaying the
received data or is not making the TNC to transmit. .......................10
Additional Troubleshooting ..............................................................11
Voltage Supply.................................................................................12
Testing for Defective IC Chips .........................................................12
TNC Programs.....................................................................................13

MFJ-1270X Instruction Manual TNC-X Packet Contoller
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MFJ-1270X TNC-X Packet Contoller
For VHF Packet and APRS
Introduction
Thank you for purchasing the MF -1270X TNC-X Packet Controller. The
MF -1270X is a new Terminal Node Controller design based on the
Chepponis/Karn KISS protocol. It is implemented using a Microchip PIC
16F628A microcontroller, a CML MX614 Bell 202 modem chip, an 8K
Ramtron FRAM, a MAX232A level converter chip, and an op-amp which
provides active audio filtering for the modem. From the beginning, this
TNC was designed to be small, inexpensive, have low power
consumption, and expandable.
The MF -1270X features an on- board USB port. The USB port was
added because the design took into consideration that computers these
days lack the old style RS-232 serial ports. There is also an 8-pin
expansion header that allows the addition of "daughter boards". Power
is provided to the daughter board through the expansion header. In
addition, signals that would otherwise go to or from a host PC can be
intercepted by the daughter board at the TTL level and processed. The
I/O on the expansion header speaks "KISS" so that any daughter board
only has to send and receive data packaged in KISS format to access
the core module. This makes the development of daughter boards fairly
simple and inexpensive. For example, daughter boards are now
available that can turn the MF -1270X into either of two types of
digipeaters via the MF -1270DG, or into a stand alone APRS Tracker
with the Coastal Chip Works X-Track board (http://tnc-x.com/).
In addition, the expansion header provides access to a second on-board
serial port. The X -Track daughter board, for example, uses this port to
receive data from a GPS receiver. The data is then processed and
formed into packets and an APRS beacon is sent. Even without daughter
boards the MF -1270X works as a fully functional stand alone KISS
mode TNC.
The idea behind the expansion options was to provide a platform that
would allow additional functionality to be added to the unit with the
investment of very little design time and very few parts.

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Power Requirements
IMPOR AN : DO NO PLUG IN HE 8-15 VDC POWER SUPPLY
AND HE 9-VOL BA ERY A HE SAME IME
The power requirements of the MF -1270X are very minimal due to
the low power consumption of the design. Using an 8-15 volt DC
power supply capable of 200-300 mA is well within the consumption
specifications. There is also a 9-volt battery snap provided for a 9-volt
battery. This makes the TNC more portable for campers and
backpackers.
IMPOR AN : DO NO PLUG IN HE 8-15 VDC POWER SUPPLY
AND HE 9-VOL BA ERY A HE SAME IME
Terminal Speed
The MF -1270X supports only 4 terminal speeds. umpers P1 and P2
determine the speed strictly for the link between the TNC and the
computer. The following settings are allowed:
JP1 JP2 Port Speed (Baud rate)
ON ON 1200 (Default Speed)
ON OFF 4800
OFF ON 9600
OFF OFF 19200
Note that the terminal speed setting does not affect the speed to transmit
data. The out-going or transmit speed is always 1200 baud. Note also
that if you set this baud rate faster than 1200 baud, it is possible for data
to be fed into the modem faster than it can transmit it over the air. This
may eventually result in the transmit buffer filling up.
Setup If You Are Using USB
If you have elected to use the USB port to provide data communications
to your PC, you should begin by acquiring and installing the drivers for
the PC and operating system that you are using. The USB IC used is an
FTDI chip. The driver you need is a Virtual Com Port (VCP) driver can
be found at :http://www.ftdichip.com/Drivers/VCP.htm if the operating
system you use does not automatically locate the drivers. It will make
the TNC appear as an additional com port on your computer so that you
can use any packet radio software that supports a KISS TNC connected
to a standard serial port.

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If you use the USB port, do not supply any power to the TNC through the
power jack.. The USB buss can supply the rather limited power
requirements for the TNC. If you are using the USB option, set the board
jumpers as follows:
JP3 On the left two pins (toward C24).
JP4 Connect the center pin to the pin that is closest to the
center of the board.
JP5 umper pins 1 and 2 (the end closest to Q1) and pins 3 and
4, unless you are using a daughter board.
Setup If You Are Using the TNC’s Serial Port
If you plan to connect the TNC to a standard computer serial port,
set up the jumpers as follows:
JP3 On the right two pins (toward U5)
JP4 Connect the center pin to the pin closest to C22.
JP5 umper pins 1 and 2 (the end closest to Q1) and pins 3 and
4 unless you are using a daughter board.
If you are using the on-board serial port, you must supply power to the
TNC. This can be done in one of two ways. There is a coaxial power jack
on the board that can be used to receive anything from 8 to 15 volts DC.
Alternatively you can connect a 9-volt battery to the location marked
BAT.
Back Connections
Aux 232 An auxiliary serial port using a MAX232 level converter. Main
purpose is for GPS input for the X-Track daughter board.

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Serial Port A standard DB 9-pin RS-232C serial port.
USB Port A standard USB port for computers that lack the old style
RS-232 serial ports.
Power 12VDC A coaxial power jack for main power input. Center pin is
positive and sleeve is negative.
RADIO A 5-pin DIN connector used to interface the radio to the TNC.
POWER: Indicates the MF -1270X has power supply voltage supplied.
RECEIVE DCD: Indicates the MF -1270X is receiving a data packet
signal from the radio.
RANSMI P : Indicates that the MF -1270X is transmitting data
signal from the radio.
Radio Setup
The radio connections are made via a 5-pin DIN chassis mounted
connector. The connector is shown below:
Din Connector Pins
These are the radio port pins and their respective functions. Match the
proper pin and its function to the same pin and function on your radio.

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Pin 1 Microphone Audio: Supplies audio from the TNC to your radio.
Pin 2 Ground: Common connection for audio and PTT common.
Pin 3 Push-to- alk: Allows the TNC to key your transmitter to transmit.
Pin 4 Receive Audio: Supplies audio from the radio to the TNC.
Pin 5 No Connection
Cables
Radio TNC Cable
Alinco8 Strd HT MF -5022
Icom1/Yaesu Radioshack Hts MF -5024
Kenwood2 Hts MF -5026
Yaesu R-Series HT MF -5020
Yaesu 8-pin MF -5080
Icom3 8-pin MF -5084
Kenwood/Alinco 8-pin MF -5086
Yaesu 8-pin modular MF -5080M
Icom4 8-pin modular MF -5084M
Kenwood 8-pin modular MF -5086M
Radio Shack 8-pin modular MF -5088M
ICOM HF 8 Pin DIN MF -5063
ICOM VHF 8 Pin DIN MF -5064
ICOM 706 13-Pin DIN MF -5065
KENW / YAESU, AZDEN VHF 6-Pin mini DIN MF -5060
KENW HF 13-Pin DIN MF -5066
5 pin DIN, MF TNC MF -5205
1 - Does not include IC-W2A
2 - Does not include 2500
3 - Does not include 25A, 255A
4 - Does not include IC-100H, IC-2700H
5 - YV for KAM VHF port, YH for KAM HF port. Other Kantronics use YV
6 - YV for KP9612 1200 band port
7 - YH models for KPC9612 9600 baud port
8 - Excludes D -100, 120T, 200, 500
Radio Connection
When using the pre-made cable for your radio, plug the cable into the 5
pin DIN connector on the MF -1270X and into the proper connector on
the radio. Depending on the cable it might be the microphone and
speaker connectors or the audio accessory connector. For a radio that
does not have a pre-made cable the MF -5202 cable is available for

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making your own adapter cable to connect to the audio in, audio out, and
PTT lines of the radio you have. Refer to the operators manual or service
manual of the radio for the correct connections.
Setup and Troubleshooting
Receive Testing
Open the squelch on the radio. When a data packet is received, you
should see the yellow LED light briefly and go out. Even when no data is
being received it is normal for the yellow LED to flicker. However, it
should come solidly on when a packet is received. Assuming that this
checks out, run a serial terminal program such as TeraTerm. Select the
COM Port that the computer issued to the TNC and set the baud rate to
whatever baud rate you specified with P1 and P2. Confirm that you are
receiving data (note, this will be raw KISS frames so much of it may look
like garbage, but you should see some recognizable data). Note that if
you are using the USB option, you must the USB drivers loaded on your
computer.
Transmit Testing
Next check out the transmit chain. The TXDelay is set by R13. Start by
setting it at about halfway (which will correspond to a TXDelay of about
240 ms (or a setting of 25 on most TNC’s). At this point you need to be
running a program on your PC that supports KISS mode. The TNC-X
webpage at http://tnc-x.com/documentation.htm has a program called
TXTest, which is a very simple program that can be used to test your
transmit chain.
When you transmit a packet, you should see the red LED come on
briefly. Hook the transmit audio and PTT up to a radio and try
transmitting. R12 is used to adjust the transmit level. 3 KHz deviation is
recommended. If you don’t have a means of measuring the deviation
precisely, monitor your signal on a receiver and slowly increase R12
until you hear no further increase in volume on the receiver. Then back
it off a bit. Even if the TNC is not connected to a radio, you should see
the red light come on when you transmit data via the TNC.
Trou leshooting
Can receive another node but can not get the node to
respond.
1. Check the interface cable. Make sure the PTT line has continuity
and is correct point on the transmitter to key the transmitter.

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2. Check the interface cable to make sure the transmit audio line
has continuity and is connected to the correct point on the
transmitter to transmit the audio.
3. Check the transmit modulation level. The deviation of an FM
transmitter should be around 3-4KHz. If it is too high or too low
then the remote node may not respond to the 1270X. Listening
to the audio and comparing it to the remote node level will get it
close to the correct level but proper test equipment is strongly
recommended.
4. Some radios require much lower audio levels than others. R11
may need to be changed from 10K to 47K if you can not turn
down the audio level smoothly to around 1-2KHz deviation. This
will show up as a sudden drop out of transmit audio at the
minimum TX level range.
5. Make sure the transmitter is on the correct frequency. The
transmitter should be plus or minus 500Hz from the desired
transmit frequency. If it is off by more than 1000Hz the signal
may be distorted enough to not decode by the remote receiver.
6. Check the transmit modulation quality. The audio should not be
clipped by any internal to the transmitter limiters. A clipped or
distorted signal will be much harder to decode (See #3 and #4
above). Check for hum and noise in the signal. The modem IC
will generate a tone when not transmitting which may be heard if
you manually key the transmitter but there should not be any AC
hum or noise from RF getting into the microphone line. If so
make sure the ground line is connected to the correct ground on
the microphone jack. Some radios have a microphone ground
and a chassis ground. Use the correct one for your radio.
Can transmit but not receive the node. Can not hear a
working node.
1. Check the interface cable to make sure the receive audio line
has continuity and is connected to the correct point on the
receiver.
2. Make sure the receiver is receiving a known good working
remote node and the receiver is on the proper frequency.
3. See if the yellow LED lights up when the remote node transmits.
Try to adjust the receive level from min audio level to where the
LED reliably lights up every time. Do not set it too high which
may cause distortion in the filters and difficult data decode.
12 0X seems to receive but the computer is not displaying
the received data or is not making the TNC to transmit.
1. Check the jumpers to make sure the 1270X is powered up and is
listening to the proper port, either the RS232 or the USB port.