Work great, then not - AX.25 Packet Connection

[Robert Cheek]

Everything was working fine for several weeks with my Ubuntu Linux 20.04LTS, PK-232, FT-8900.  I could send and receive emails via two of my local gateways without fail.  Last night and today that has come to a halt.  When I connect, the connection is quick, I see an email is to be received but the TNC suddenly stops responding and I get the "unexpected EOF" error. 

Here is a screen shot:

2021/08/17 21:27:28 Starting HTTP service (localhost:8080)...
2021/08/17 21:28:14 Connecting to AB4NX-10 (ax25)...
2021/08/17 21:28:21 Connected to AB4NX-10 (AX.25)
Welcome to the Georgia ARES Hybrid Gateway
[WL2K-5.0-B2FWIHJM$]
;PQ: 85450160
CMS via AB4NX >
>FF
;PM: N4RFC NLIL491Z92RD 156 N4...@winlink.org Another Test
FC EM NLIL491Z92RD 170 156 0
F> AC
1 proposal(s) received
Accepting NLIL491Z92RD
Receiving [Another Test] [offset 0]
Another Test:  70%
2021/08/17 21:30:05 Exchange failed: unexpected EOF

It might fail at 50 to 60 percent completed, it might fail even before the message transmission started.  I can hear the gateway sending packets but my TNC stops responding. 

Something has changed, but I can't say what it is.  Ubuntu did an update, could a library have gotten upgraded?  I am not doing anything different.  Signal strengths are good and traffic is low on this channel. 

Any ideas?

Bob - N4RFC

[Ed Fardos]

I spent a while with a similar situation.  In my case the notch-filter was enabled on the radio.

-craig
KM6LYW

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[Mike Lussier]

I have seen this very thing on both Ubuntu 21.04  and a raspberry pi.  The fix that I found was to bring down and restart ax25 . if that didn't do it I kill kissattach, stop ax25 and reboot. Then everything started working again. 

[Robert Cheek]

No notch filter on this FM radio.

I have checked the squelch, and all is as I normally operate.

[Robert Cheek]

I have tried stopping and starting ax25, and I have tried rebooting.  I also refreshed my kissparams also.  I may try with some changes on the params.

Thanks,

Bob

[jack.h...@gmail.com]

Bob, let us know if something works. I'm in a similar boat here, but then my local Winlink packet node is not 100% dependable. 

I generally only find this out twice a week: for Virginia Winlink Wednesday and the American Legion WINLINK on Fridays.

Jack

NG2E

[Jim Weisgram KJ7DMV]

If you have the luxury of a second nearby Winlink gateway, it is can be a good thing to try that connection before you troubleshoot your own setup too hard.

>> Jim

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[jack.h...@gmail.com]

Jim,

Thanks for the advice! Nearby is relative. I have two other stations in the area, but I've never been successful hitting any but the gateway in question.

Jack

[jack.h...@gmail.com]

I am back in business. The problem was at the gateway. Gateway owner rebooted everything incl the TNC. Working like a charm.

Jack

[Robert Cheek]

I did some more testing and found that I only had the failure on receiving messages, not sending them.   When the message times out there seems to be a "failure to communicate" between the computer and the TNC.  When I try to stop the ax25 with

sudo systemctl stop ax25

that command hangs and does not return to the terminal.  I then have to reboot the TNC and reboot the computer or nothing works.  If stopping ax25 works and returns to the terminal prompt then I can restart another session and it will work. 

I also found that it was associated with one of two gateways. I have asked that sysop to reboot his gateway (these guys are using winders 10, they should be rebooting daily!)  and I will see if I can receive a message after than.  I also noticed that a very short, one line message will come through, make it to the inbox and then the system hangs.  A longer, (10 lines + ) hangs before the message is completed.

DE N4RFC

[Robert Cheek]

I tried to use the serial-tnc to send viamy PK-232 packet.  I edited the config file and can now issue a connect via serial-tnc.  The problem is I need about 300 ms of TXdelay to get to the node, and the serial-tnc sets 120 ms.  I tried to override that on the command line as I saw done with HBaud,

"pat connect serial-tnc:///nodecall-10?TXdelay=300" but no joy.  The TNC was still set to 120 ms.  The setup strings appear to be hard coded?  Where are they and how can I change them?  Acutally, can I just do away with TX delay and leave it set at 300 which is what I use all the time with the nodes?

DE N4RFC

[Robert Cheek]

Well, I have been playing around with this for a couple of days now and I have found that no matter how short the message is at some point it it going to time out.  When it does running sudo systemctl stop ax25 will not work, it hangs.  Requires rebooting everything.  I put another TNC on to monitor the RF side, before the timeout the AX25 just stops receiving, the gateway it keeps sending until it times out and sends a disconnect.

Can someone point me to the module in the source where the serial-tnc is?  And, directions on compiling PAT?  The TNC/FT-8900 works without fail on Winlink Express, so I want to run pat with the serial-tnc option as I think that will be more reliable.

Thanks,

Bob - N4RFC

[Robert Cheek]

I tried a fresh install and I was able to get a AX25 connection to work a couple of times then started failing the same way, it would just hang during a message download.  Very random.  I have installed GO and downloaded source and seems to have worked building from source, but didn't fixe the problem. Sometimes messages go through, sometimes not.  So know I am back to Serial-TNC.  I have looked through the source and I don't see where the TXdelay that shows up in the initialization of the TNC is coming from.  Can someone point me to the file where this is set so I can add some TXDelay and get PAT working in Serial-TNC mode?

N4RFC

[Mike Lussier]

did you look at kissparms  

#!/bin/bash

echo "Starting Direwolf"

#

# startup Direwolf

rm /tmp/kisstnc

#

sudo /usr/local/bin/direwolf -c /home/pi/direwolf.conf -p -L /var/log/direwolf.log

#

sleep 3

# Start Kissattach

# Attach axport wl2k to the KISS TNC at /dev/ttyXX

sudo /usr/sbin/kissattach /tmp/kisstnc wl2k

sleep 3

# Set kiss params (txdelay 300ms, txtail 10ms, persist 80 and half duplex) for port wl2k

#sudo /usr/sbin/kissparms -p wl2k -t 350 -l 10 -s 12 -r 80 -f n

/usr/sbin/kissparms -c 1 -p wl2k -t 350 -l 50 -r 80 -f n

#

#

echo "Kiss started and parameters have been added"

#

 SYNOPSIS

       kissparms  [-c  crc-type]  -p  <port> [-f y|n] [-h hw] [-l txtail] [-r pers] [-s

       slot] [-t txd] [-e feclevel] [-v] [-x] [-X raw]

DESCRIPTION

       Kissparms is used to dynamically configure KISS TNCs that have  been  setup  for

       AX.25  use by kissattach.  This program uses the packet interface to allow it to

       communicate with the KISS TNC without interrupting the AX.25 data stream. There‐

       fore  the  KISS  parameters  may  be set at any time during the operation of the

       AX.25 port.

       A full description of the KISS protocol can be found in the  ARRL  6th  Computer

       Networking  Conference  papers  pp  38-43. While use of the Tx Tail value is now

       deprecated, it has been included to satisfy the requirements of users of old TNC

       firmware.

       Although  this  utility  was  originally designed for controlling KISS TNCs con‐

       nected to a serial port, it is used by a number of other Linux packet radio  de‐

       vices  such  as the Z8530 SCC driver for controlling their parameters in exactly

       the same manner. Therefore kissparms functionality extends  to  more  than  KISS

       TNCs.

OPTIONS

       -c crc-type Sets the crc-type to use. For e.g. kernel mkiss: 0 = auto, 1 = none,

                   2 = flexnet, 3 = smack

       -p port     Sets the port that is being configured.

       -f y|n      This sets the TNC into either full  duplex  ``y'',  or  half  duplex

                   ``n'' mode.

       -h hardware This is used to set hardware specific parameters.

       -e FEC error correction level

                   Sets  the FEC error correction level in a DSP card based modem (KISS

                   parameter 8). Larger correction level means better noise resistance,

                   but  slower throughput on a good connection. This is an experimental

                   feature found in a QPSK modem for the Motorola DSP56001  based  DSP4

                   and EVM cards only.

       -l txtail   Sets  the TX Tail time in milliseconds. Note that the command to the

                   TNC only operates in steps of ten milliseconds, so only  use  values

                   like 10, 20 etc.

       -r persist  Sets  the  persist value. This parameter is scaled to the range 0 to

                   255.

       -s slottime Sets the slottime in milliseconds. Note that the command to the  TNC

                   only  operates in steps of ten milliseconds, so only use values like

                   10, 20 etc.

       -t txdelay  Sets the TX Delay in milliseconds. Note that the command to the  TNC

                   only  operates in steps of ten milliseconds, so only use values like

                   10, 20 etc.

       -v          Display the version.

       -x          Takes the TNC out of KISS mode back into ``normal'' mode. This  com‐

                   mand  is  manufacturer specific but works in many cases. This option

                   overrides all options except the port number.

       -Xraw       Sends the specified raw value to the kiss driver.

[Robert Cheek]

Mike,

Yes, I did try bunches of changes to KISSPARMS, basically what I had is what your example was, except, -c, I did not set the CRC.  But that worked because I was able to connect and get messages some of the time. 

kissparms -p wl2k -t 500 -l 10 -s 12 -r 80 -f n

[Mike Lussier]

Have you ever considered that the problem wasn't at your end but at the digipeater or the RMS Gateway. I have seen where a linux rms gateway was the cupret and that the windows rms gateway worked flawlessly. I have seen a digipeater work on on gateway and not on another only because the digipeater was off frequency enough and the modulation was above the 5khz causing distortions. no one thinks about things like this. slap it together and let it play. 

I'm not saying that pat is flawless and that ax25 and kiss aren't at fault here but you do have to step back and look at the big picture. I know that my linux RMS gateway can't handle large messages. I have to go to another rms gateway that runs windows to get those messages and they download just fine. I have been through that particular gateway with a fine tooth comb and I have tested using the same message with limited number of calls and it works. but to tell some of these folks that run these winlink nets that, they won't listen and I can't find any further answers to solve the problem but I know where it is. 

[Robert Cheek]

Mike,

Yes, went down that road briefly.  One of the two gateways I use regularly is operated by a guy I know from the local radio club.  He has been helpful in testing this problem with me.  He has made some adjustments that I requested on his Winders powered gateway. 

I also tried a different PK-232, radio, and antenna.  No Joy.  I have a Kantronics TNC here somewhere but haven't found it yet!  I would like to find it and eliminate the possibility that it is the KISS mode on the PK-232.  I have also ordered a TAPRN Nino TNC kit that I want to try.  Should be here next week, and I will get that built up and test with it, again, to eliminate the PK-232 in case it is the problem. 

One of the two gateways I use is via a DIGI, the other is direct.  They will both hang at the same % on a message.  I am using small messages for testing, one liners basically.

I want to get the system up with PAT on linux to get away from Winders.  I have this notebook to go with my GO Box that is dual boot and I have everything I need on native Linux except Winlink access.  So, I want to test PAT with serial-tnc and see if that is reliable on the PK-232 as Winders Winlink is.  If I get that going, I will continue to test the KISS mode and see if I can figure out what my problem is. 

Winlink has to be reliable to use for ARES and usable with my GO Box. Our ARES group uses Winlink for most of our communications.

Thanks for you input Mike.  I will keep at and get it figured out. 

Regards,

Bob - N4RFC

[Robert Cheek]

So, I have read that the setup for the TNC in SerialTNC mode is hardcoded.  I have downloaded and looked (and grep-ed) the code looking for where the setup strings are sent to the TNC.  Can't find it....there is a long list of commands to setup the TNC:

2021/11/11 17:25:00 Connecting to AB4NX-10 (serial-tnc)...
2021/11/11 17:25:03 Timewave PK-232M Data Controller
2021/11/11 17:25:03 Copyright (C) 1998 by
2021/11/11 17:25:03 Timewave Technology Inc.
2021/11/11 17:25:03 Release 10-Aug-98
2021/11/11 17:25:03 Ver. 7.2
2021/11/11 17:25:03 cmd:ECHO OFF
2021/11/11 17:25:03 FLOW OFF
2021/11/11 17:25:03 XFLOW ON
2021/11/11 17:25:03 LFIGNORE ON
2021/11/11 17:25:03 AUTOLF OFF
2021/11/11 17:25:03 CR ON
2021/11/11 17:25:03 8BITCONV ON
2021/11/11 17:25:03 NEWMODE ON
2021/11/11 17:25:03 Echo      was ON
2021/11/11 17:25:03 Echo      now OFF
2021/11/11 17:25:03 cmd:Flow      was OFF
2021/11/11 17:25:03 Flow      now OFF
2021/11/11 17:25:03 cmd:XFlow     was OFF
2021/11/11 17:25:03 XFlow     now ON
2021/11/11 17:25:03 cmd:?What?
2021/11/11 17:25:03 cmd:?What?
2021/11/11 17:25:03 cmd:CR        was OFF
2021/11/11 17:25:03 CR        now ON
2021/11/11 17:25:03 cmd:8Bitconv  was ON
2021/11/11 17:25:03 8Bitconv  now ON
2021/11/11 17:25:03 cmd:NEwmode   was OFF
2021/11/11 17:25:03 NEwmode   now ON
2021/11/11 17:25:03 cmd:MYcall    was N4RFC
2021/11/11 17:25:03 MYcall    now N4RFC
2021/11/11 17:25:03 cmd:HBaud     was 1200
2021/11/11 17:25:03 HBaud     now 1200
2021/11/11 17:25:03 cmd:PACLen    was 128
2021/11/11 17:25:03 PACLen    now 128
2021/11/11 17:25:03 cmd:TXdelay   was 50 (500 msec.)
2021/11/11 17:25:03 TXdelay   now 12 (120 msec.)
2021/11/11 17:25:03 cmd:PErsist   was 160
2021/11/11 17:25:03 PErsist   now 128
2021/11/11 17:25:03 cmd:SLottime  was 30 (300 msec.)
2021/11/11 17:25:03 SLottime  now 5 (50 msec.)
2021/11/11 17:25:03 cmd:FUlldup   was OFF
2021/11/11 17:25:03 FUlldup   now OFF
2021/11/11 17:25:03 cmd:MAXframe  was 4
2021/11/11 17:25:03 MAXframe  now 6
2021/11/11 17:25:03 cmd:FRack     was 2 (2 sec.)
2021/11/11 17:25:03 FRack     now 5 (5 sec.)
2021/11/11 17:25:03 cmd:RESptime  was 1 (100 msec.)
2021/11/11 17:25:03 RESptime  now 1 (100 msec.)
2021/11/11 17:25:03 cmd:NOmode    was ON
2021/11/11 17:25:03 NOmode    now ON

Where is this hard coded?  All I want to do is change a TXD so my TNC will have time to come up before it is keyed off.

Is there someone out there than can tell me where this code is, cause I can't find it.

Hello?

DE N4RFC

[Robert Cheek]

Here is some more information on this problem.  I realized that I could send a short message and it would work, but longer messages would time out. 

Once more I did a fresh install, removed PAT .11 and AX5 tools and apps.  I manually removed all directories (that I could find) installed by PAT and AX25.  Then I reinstalled PAT .12 and AX25.  After the fresh install I could again send short messages and longer ones hung. 

Thinking I may have a problem with my old PK-232 TNC, I got another one (same rev firmware but a newer unit) and had the same results.  I got hold of Kenwood TM-D710 with built in TNC, so now I have a different TNC and Radio and had exactly the same problem.  Receiving a message would hang at the same point. This particular message hung ad 27%, every time.  I could hear the Gateway sending packets, I could see the RX Data receive LED flashing on the USB/Serial interface, but the computer was just not responding. 

Tuned another radio and TNC to the channel and and set it to monitor the transaction.  This is what I found.

This is a trace of the failing transaction on packet radio.  From the packet radio computer that is sending the transaction, TM-D710 TNC/VHF radio using the Kenwoods internal TNC.  I am using https://fmarier.org/ script to initialize the TM-D710.

Sending from the command line:

 bob@bob-HP-Notebook:~$ sudo systemctl start ax25
[sudo] password for bob:
bob@bob-HP-Notebook:~$ pat connect ax25:///ab4nx-10
2021/11/20 13:55:56 Connecting to AB4NX-10 (ax25)...
2021/11/20 13:55:58 Connected to AB4NX-10 (AX.25)

Welcome to the Georgia ARES Hybrid Gateway
[WL2K-5.0-B2FWIHJM$]

;PQ: 41851908
CMS via AB4NX >
>FF
;PM: N4RFC 3JPG31NQP11V 359 prvs=095849a8c6=b...@n4rfc.com Re: Friday Test Message
FC EM 3JPG31NQP11V 959 359 0
F> A1
1 proposal(s) received
Accepting 3JPG31NQP11V
Receiving [Re: Friday Test Message] [offset 0]
Re: Friday Test Message:  27%       ** this is where the transaction hangs on the packet computer
2021/11/20 13:57:07 Exchange failed: read wl2k: connection timed out
bob@bob-HP-Notebook:~$ sudo systemctl stop ax25
bob@bob-HP-Notebook:~$

This is the trace from the monitoring TNC.  This is a PK-232 TNC is set to monitor level 6.

N4RFC*>AB4NX-10 [C,P] 61 F6
AB4NX-10*>N4RFC (UA,F)
AB4NX-10*>N4RFC [I;0,0]:

Welcome to the Georgia ARES Hybrid Gateway

N4RFC*>AB4NX-10 (RR;1) BB 40
AB4NX-10*>N4RFC [I;0,1]:
[WL2K-5.0-B2FWIHJM$]
N4RFC*>AB4NX-10 (RR;2)
AB4NX-10*>N4RFC [I;0,2]:
;PQ: 87166537
AB4NX-10*>N4RFC [I;0,3]:
CMS via AB4NX >
N4RFC*>AB4NX-10 [I;4,0]:
;FW: N4RFC
[Pat-0.12.0-B2FHMG$]
;PR: 43580631
; AB4NX-10 DE N4RFC (EM74td)
N4RFC*>AB4NX-10 [I;4,1]:
FF
AB4NX-10*>N4RFC (RR,F;2)
AB4NX-10*>N4RFC [I;2,4]:
;PM: N4RFC 3JPG31NQP11V 359 prvs=095849a8c6=b...@n4rfc.com Re: Friday Test Message
N4RFC*>AB4NX-10 (RR;5)
AB4NX-10*>N4RFC [I;2,5]:
FC EM 3JPG31NQP11V 959 359 0
AB4NX-10*>N4RFC [I;2,6]:
F> A1
N4RFC*>AB4NX-10 [I;7,2]:
FS +
AB4NX-10*>N4RFC (RR,F;3)
AB4NX-10*>N4RFC [I;3,7]:    ** This is where the transaction hung
Re: Friday Test Message0Azmfo{]^,[o,nn~S4//GJZI#(_( M}
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [RR,P;3]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
AB4NX-10*>N4RFC [D,P]
N4RFC*>AB4NX-10 (RR;0)
N4RFC*>AB4NX-10 (RR,F;0)

You can see on the monitor trace that the Winlink Gateway sends a RR packet but the PAT computer never responds.  Finally the Gateway tries disconnects.  At that point I stopped the AX25 (sudo systemctl stop ax25) and the AX25 would send a RR packet and return to the command line.  The PAT computer errors out with " Exchange failed: read wl2k: connection timed out"

This could be setting, I have changed a bunch of them but nothing makes any difference.   The time out seems to be pretty short, but the root problem appears to be the PAT machine just stops responding.

Again, any one have and idea?

Also, I have looked high and low through the GO source for the TNC initialization in Serial-TNC mode, can't find it.  I would love to run the PK-232 in Serial TNC mode, but the base config does not have enough TXDelay for my system. Can someone explain how and where the serial TNC initialization is?

Regards,

Bob - N4RFC

[hare...@gmail.com]

Hi Bob,

hmm that reminds me of a problem I had with a PACTOR modem in the past.

Try a 

stty -F /dev/YOURSERIALDEVICE raw

I had the problem that 0x11 got lost to my PACTOR modem and I fixed that by setting the device back to raw. Here is an excerpt of an old email exchange I had with SCS:

pi@funkpi:~/go/src/github.com/la5nta/pat $ stty -F /dev/ttyUSB1
speed 9600 baud; line = 0;
-brkint -imaxbel

-->  0x11 are lost

pi@funkpi:~/go/src/github.com/la5nta/pat $ stty -F /dev/ttyUSB1 raw
pi@funkpi:~/go/src/github.com/la5nta/pat $ stty -F /dev/ttyUSB1
speed 9600 baud; line = 0;
min = 1; time = 0;
-brkint -icrnl -imaxbel
-opost
-isig -icanon

--> 0x11 are passed to the modem again.

Hope this helps (otherweise I have no experience anymore with PACKET RADIO, it's pretty much dead here in central Europe).

73s and good luck

 

 Torsten DL1THM

[Robert Cheek]

Torsten,

I gave that a try and on three test messages using the TM-D710 the were sent and received without hanging! 

I will continue to test, but I think you may well have solved my problem!  Thank you very much for reading my post and taking the time to give me your experience.

73 and good DX,

Bob - N4RFC

[Robert Cheek]

The stty -f /dev/yourport raw command has fixed my problems with the transaction hanging.

Also, I just confirmed that the NinoTNC from TARPN works with PAT.  I am using it on 2 meter 1200 baud packet but it has other modes and speeds:

• 1200 baud AFSK AX.25 -- 1984 packet radio
• 1200 baud AFSK IL2P
• 2400 baud DAPSK AX.25
• 2400 baud DAPSK IL2P
• 4800 baud GFSK AX.25
• 4800 baud GFSK IL2P
• 9600 baud GFSK AX.25 -- G3RUH-like
• 9600 baud GFSK IL2P

It is a kit, takes about 2 hours to assemble and all in is about $40.  Good value. 

Bob - N4RFC

[hare...@gmail.com]

wb4...@gmail.com schrieb am Mittwoch, 24. November 2021 um 18:27:23 UTC+1:

The stty -f /dev/yourport raw command has fixed my problems with the transaction hanging.

Glad I could help! Will try to put that command to Pat's Wiki, now we're sure it might be useful for others as well.

73s and good contacts

 Torsten DL1THM