AEA PK-232/software problem

Discussion in 'General Technical Questions and Answers' started by Guest, Mar 27, 2005.

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  1. Guest

    Guest Guest

    another question... I have an AEA PK-232 and running PCPackRatt. The TNC will show that it is receiving with the "Tune" display. I will send out "packets" to other stations, but when they attempt to send something to me, my TNC will NOT send the information back to the computer. This is a real head scratcher. I don't know what to do.
  2. W9GB

    W9GB Ham Member QRZ Page

    Brandon -

    This sounds like that your specific computer serial (COMx) port is DEAF (can't hear the TNC talking) OR the computer is fine, BUT the TNC is MUTE (can't talk to computer).

    What could cause this?

    1.  TTL to RS232 hardware (IC) in TNC has failed.
    In the 1980s this was a 1488/1489 driver (integrated circuit) combination.  Very popular in IBM-XT and IBM-AT days.  The original AST 6-pack add-in card used this combination for its serial ports.
    For the past 20 years most designers are using the Maxim/Dallas MAX232 (TTL-to RS232 converters).  The schematic diagram in your manual should show which one your TNC is using.  Trace back from TNC serial port to first IC you reach

    2. Bad cable between TNC and computer.
    Pinched or cut wire, cold solder joint, bad pin crimp, or improperly wired homemade serial cable.

    3. Bad serial port on computer - RS232 to TTL converter.
    Similar to #1.  This converts the RS-232 serial protocol back to TTL ("transistor to transistor logic" - used to describe digital based signal levels). This serial port may be integral to the motherboard OR may be an add-in card to the computer.
    You can also have serial port driver issues (IRQ conflicts) with your operating system (e.g. Windows)

    To diagnose, you have to test ("assure") that each of the following 3 components are working.

    I would: Test the cable and then try the TNC on another serial port of the computer.
    How to check - what works.

    Tools / software needed:

    Volt Ohm Meter (VOM)
    Pin-out diagram for a "straight through" serial cable
    Hyperterminal program
    The VOM can verify that # 2 (serial cable) is working properly.

    IF the TNC works properly (listens and talks) with another computer, then TNC is okay (and it is not #1).

    You can assure #3 by attaching another external devices (e.g. external modem) and works properly
    OR use HyperTerminal to have a terminal session with the TNC.  
    IF you can see TNC start-up screens when using HyperTerminal - then the receive section of your computer's serial port is OK.

    IF the TNC responds to your commands typed through HyperTerminal, then the trasnmit section of your computer serial port is OK.

    IF everything checks OK, then your HARDWARE is working and you have a SOFTWARE problem -- most likely with the PC application you installed !!

  3. K8JDC

    K8JDC Ham Member QRZ Page


    I have a couple of thoughts on this.

    First, the PK-232 uses a 25-pin D connector to the computer. Your computer probably uses a 9-pin D serial connector. Therefore, you're probably using a 25-to-9 pin adapter in the cable. There are 3 different wiring conventions used in 25-to-9 adapters (1-9 straight through, standard RS-232, and null modem RS-232). These 3 wiring conventions place transmit data, receive data, and control signals on completely different pins. I would check to make sure your wiring is correct. You can download RS-232 pin definitions for 9-pin and 25-pin connectors and refer to the PK-232 manual for pinout info.

    Second, it sounds like you are trying packet mode. My PK-232 will not properly "receive" (decode) packets from my Icom 746 radio if the noise reduction circuitry is engaged on the radio. When I run VHF packet, I turn off the NR and noise blanker. It works fine this way, but won't work otherwise. So, if you have any DSP stuff going on in your radio, this could be an issue. I would try to turn it off.

    Those are the first things that come to mind. Good luck.

    Dave / K8JDC
  4. G7JAV

    G7JAV Ham Member QRZ Page


    When I first went into Packet with a AEA PK 88 I had truoble sending and receiving. One of the tests was to make a test plug for the TNC which virtually sent the output of the TNC bac into itself ie: audio from the TNC connected to the RX audio to the TNC.
    One other thing I had problems with is the TNC had gone out of sinc/tune. It took a whole year to find an out of print manual to get the instructions to put it right. The users hand book was no help at all.
    If you like I could copy the relevant page and either e-mail or post it to you.

    Hope this was some help
  5. WA9UAA

    WA9UAA Ham Member QRZ Page

    To echo G7JAV, connect the audio IN and audio OUT wires together on the far end of the PK 232 to radio cable, be sure you have your call in the TNC i.e. MYC <yourcall> type 'C' 'yourcall' from the command prompt and see if you get a 'connected to <yourcall>' on the computer. GL HTH
    Rob WA9UAA
  6. W5RKL

    W5RKL Ham Member QRZ Page

    If you can't get anything displayed on your computer screen from the PK232 then there are 4 possible problems.  

    1.  The PK232 serial port has failed, doesn't work

    2.  The Pk232 serial ports data rate (baud rate) is different than your computers serial port baud rate.

    3.  The PK232 PROM has failed

    4.  Wrong type of serial cable.

    Basically all you need between the PK232 and your computers serial port is

    Computer serial port              PK-232

    Pin                                      Pin

    2   ------------------------------   3
    3   ------------------------------   2
    7   ------------------------------   7

    This is a basic serial port wiring.  When using this make sure you turn OFF "Hardware handshaking" in the software terminal program, it's not needed.  Until you get familiar with serial communications, how CTS, RTS and CD work, turn hardware handshaking off.  The PK-232 can and will use those lines but for now, don't use them.

    Once you have the ports wired as show above, launch your terminal program and configure it for 300 baud, 8 bits, 1 stop bit.  Now power the PK-232 on, leave the radio off.  Look on the screen and if the PK-232 and your computers serial ports are the same speed (baud rate) you will see the AEA ROM data displaed on the screen.  Press "return" and you should see a short menu.  If this works then you can communicate with the PK-232.  If you do not see anything then reconfigure the terminal program to the next higher speed (baud rate), power the PK-232 off and back on again.  If you see the AEA ROM info then you've found the speed at which the PK-232 is set.  If you still don't see anything, continue going higher in speed until you see the AEA ROM info.  You can also try different settings for bits, i.e. 7 verses 8.  The command to reset the PK-232 is "reset".  This command will reset the PK-232 to the factory defaults, remove any callsigns that may have been configured and set all the variables to factory default.


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