PC FlexNet with a DRSI Card
by Charles Brabham N5PVL
Many Hams have expressed an interest in upgrading their Packet stations by changing over to the use of FlexNet, with it's easy set up, advanced design and high performance. Here is a step-by-step account of how to go about doing this if you own a DRSI PCPA type HDLC card. Though the details of this setup may differ slightly from yours, it is still hoped that this will serve as a general guide. I will be setting up an individual Packet station here, not a node.
The computer I will be using for the purposes of this article is a 33 MHz 386DX PC, with an 80 MB HD and monochrome VGA monitor.
I'll be using a DRSI PCPA-1 TNC, using only the 1200 baud TNC on port one, and with nothing connected to port two.
The Radio is a Kenwood TM-241a, hooked up to a Ringo Ranger at 30 ft.
The software to be installed will be the DOS version of FlexNet, along with a special FlexNet port of the BCT terminal program.
Getting the Software
The first thing to do is to get a copy of the software at the FlexNet web-site:
FlexNet Home Pagehttp://www.afthd.tu-darmstadt.de/~flexnet/
The Flexnet page has information about the FlexNet E-mail support list, the new Win95 version of FlexNet, and there is also a link called "Downloading Information". Click this and when it comes up, read the information there carefully, then go on to the "Directory Page".
PC FlexNet is modular in design, which means that you only use the program modules needed for your particular setup. This results in a smaller, easier to expand and modify suite of program modules rather than having one large, bug-prone and hard to de-bug program that "does it all". In fact, the entire package can be run from a floppy disk, if you choose to do so, with room left over.
I use the hard-drive because it's faster and it's there, but my first setup was on a floppy so that if I got it wrong I could always pull the floppy, reboot and use my old software while I tinkered with FlexNet. This precaution turned out not to be necessary, as setting up FlexNet is generally very easy and uncomplicated. Not much tinkering was called for.
From the Directory page, I will download the following files:
This file contains the kernel, as well as several utilities used for setting up and operation. It also contains the docs.
This is the driver module for DRSI cards, and a variety of other HDLC cards.
This is a port of the BayCom "BCT" terminal program for FlexNet.
After downloading the files, I'll create a new directory called C:\FLEX , and decompress the files into the new directory using the LHA.EXE file compression/decompression utility. The command is: LHA E [filename.lzh] as in: LHA E PCF.LZH
Setting Up the Software:
At this point, there isn't much left to do. An initiation file for the BCT term program, INIT.BCT, must be configured to suit your station, and a batch file FLEXUP.BAT must be created which will call and load the program modules, then set the station parameters. This is a good time to become familiar with the docs.
Don't panic! The first half of this file is in German, but halfway down, the entire thing is repeated in English. What I do is put FLEXNET.DOC into a text editor and delete the German part, then save the file.
There is an example batch file in FLEXNET.DOC which will work for my purpose with very little modification, so I cut 'n pasted that part of the docs into FLEXUP.BAT, then modified it to look like this:
(Leave out the comments on your copy.)
LH FLEXNET 20
if errorlevel 1 goto end
LH XSCC -t:DRSI -c:1 DRSI card, port 2 disabled
if errorlevel 1 goto error
FSET mode 0 1200c 1.2 kb, soft DCD option enabled
FSET txd 0 15 TXDELAY set at 150 ms.
That's it. The batch file uses the FSET.EXE utility to tell FlexNet what speed to transmit at, and set the TXDELAY to suit your radio. Most radios will work at the setting above, but you may need to go slightly higher. Keep the TXDELAY as short as you can reliably get away with.
All other TNC parameters such as FRACK, PACLEN, MAXFRAME, RESPTIME, PPERSIST, and so on, are all automagically adjusted as you operate by the software, so you don't have to worry about them.
I chose to use the soft DCD option so that I could run a wide open squelch. This improves performance, and gives you one less thing to adjust properly. (or improperly!)
This would be a good time to look carefully at FLEXNET.DOC, being sure that you understand what each line of the batch file does.
The docs for BCT are in German only, but fortunately, INIT.BCT is easy to set up and understand.
I set mine up for VGA Monochrome, first window 5 lines high, middle window 18 lines high, no screen-saver:
Some of the parameters I could not figure out, so I left them alone and this has worked out well.
; --- packet interface ---
; --- screen outline ---
sa_color 02 47 CF 07 47 40 57 03 02 17 1E 5E 04
sa_mono 07 70 F0 07 70 70 0F 07 0F 70 07 70 70
; --- remote ---
rcmd CSTATUS DIR QUIT READ RPRG WRITE WPRG
boxcalls DB0??? OE?X??
; --- signals ---
; --- input behaviour ---
; --- file parameters ---
; --- default save files ---
write 0 OFF
write 1 OFF
write 2 OFF
write 3 OFF
write 4 OFF
write 5 OFF
write 6 OFF
; --- standard text ---
st B BayCom-Terminal
st C \x:c \i
st D \x:d
st G Gruss ... \z
st Q Hawediehre!
st Z Default-CTEXT
; --- save qso context (do not edit!) ---
; --- end ---
In theory, after editing these files to suit, you should be able to run FLEXUP.BAT and when it finishes loading, run BCT and be ready to go.