Remote update using 3rd party programs.
This chapter is copied from the DIGI_NED website which can be reached through
the DIGI_NED portal at http://www.qsl.net/digi_ned
The APRS network very often uses digipeaters on high
locations in rural areas or buldings in urban areas who cannot be entered easy
due to owners restrictions or security policy's. In
this case it is needed to be able to do some maintenance to the system without
being there. Mantenance can vary from small parameter changes to updates of
In the situation of the DIGI_NED digi
PI1APA, it was not possible te access the building during evening and night.
So the remote access was required. The here discribed
solution can be copied but needs adaption to your own specific configuration
The basics of the DIGI_NED remote access are simple:
- Stop the digi software remotely
using the !exit commando and,
- restart support software
with OS functionalities ( OS stands for Operating System )
- Download required files using file transfer,
- edit configuration files locally,
- Upload the edited files or new release of software,
- Stop the support software,
- reboot the hardware by command or some hardware switch
- Restart the digi software.
Starting the support program.
As the system boots the autoexec.bat runs the default
sub from the menu. This DOS menu enables attended mantenance to boot without
the digi software.
PROMPT DIGI_NED $p$g
ax25_mac.exe -poscc:158:5:4444 -b1200:1200:1200:1200 -L -F -C17 -BU50
if errorlevel 4 goto net_start
@echo type ctrl-c to exit
After DIGI_NED has stopped, the exit commando lets the
batch-file select the next step. In our case exit code 4 starts the support
software NETchl. All other exit codes makes the system reboot.
When NET is stopped the "autoexec.bat" runs
a program named "boot" after a short wait program. this program, wait
or pause, as you have available, enables the sysop to interfer with the normal
programma loop as the system is attended.
The support software for example NETchl
provides services for file transfer and to execute dos commands like copy and
delete on the remote system.
As NETchl is a tcp/ip package for amateur use in a DOS
environment it fits completely to our needs.
Due to complexity of the package the full functionality
will not bediscribed in this documentation. A full sample
configuration is available for download including doc's.
The available package at the DIGI_NED web-site is 800 Kbyte and contains
Keep in mind that you need some experience of tcp/ip
in combination with AX25 amateur packet radio !
The features used from the NETchl package are:
- FTP, get, put,
- RCMD, normal DOS commands such as copy and delete.
FTP, File Transfer Protocol must be clear. RCMD is a
telnet session to a specific port in NETchl (459). This port uses 'Baycom authentification'
from a text string in a file in "c:\net\rcmd\remote_host_name". After
this the console prompt of the remote system is offerd to you.
It is also possible to use other packet-radio programs
for this purpose. The minimum requrement is that you have to be able to reset
the system remotely.
Isues on transferring data on APRS frequencys:
In the PI1APA system 2 ports are available. 1 port on
VHF and 1 port on UHF. When in service mode, digi_ned is stopped and NETchl
is running, we use the quiet UHF APRS frequency for up and downloading. It is
good to have a separte frequency for up and downloading. Think of what happens
when we load the APRS QRG with heavy tcip/ip up- or down-load traffic ! In such
a case all resources will be used by the up- or down-load and nothing is left
for the APRS users. Keep in mind that a wide commonly is placed at high altitude
! and has large coverage !
Practice learned that uploading digi_ned.exe at 1200
bps simplex takes about 30 minutes ! You can decrease required upload time by
takin out all comments in the configuration files.
In case you do not have 2 or more ports available think
seriously of some way to make your transmitter go QSY for the period required
to do maintenance !
If you have more than one port it is also possible to
equip the APRS transmitter with both a 1200 bps AFSK modem and a 9600 bpq G3RUH
modem. It will decrease upload time and load on the APRS QRG !
As you can see there are many possible solutions. Probably
you can think of more !.
Resetting the system and watchdogs. After
the maintenance the system has to be reset to make the changes active. In NETchl
a 'exit !' commando is available. Also the 'shell /c boot' command makes the
In case the support software is not able to do so you
have to reset the system by some other command. The packet radio node PI1VRZ
and dx-cluster PI8DXW can be reset using a ZVEI tone code sequence ( sel-call
). It is even possible to use DTMF commands. On these topics you imagination
is the limit !
To be sure the system not hangs we also use a watchdog.
watchdog examples are available at the VrzApDxw web-site.
Due to the high flexibility of DIGI_NED on all items DIGI_NED is the solution
in many cases. In the folowing cases we will discribe what DIGI_NED can do.