Batboard

Hi. A couple of weeks ago I acquired an apparently unused VHF GP300 radio body made around 1994. It appears to work and puts out about 6W on whatever frequency it is currently set up for. I am a radio amateur and want to use it on the 2m band.

I purchased a Maxton RPC-M300 programming interface, which came with a CD containing the programming software. The version of the software also dates from around 1994. I installed it on a 2002 vintage Toshiba Satellite 1800 laptop which has a serial port, on which I installed Windows 98 to get access to MS-DOS.

There is no information supplied with the interface. I fitted it to the back of the radio. I presume that the red and black wires are used to supply power to the radio so I applied 7.5V to start off with, later I tried 9V. The other connectors (one like a telephone plug and the other a stereo headphone jack) I presume are for other types of radio the interface can be used with, so I didn't use them.

The red light comes on as soon as power is applied. The software is set to COM1. If I do the communication test with the radio switched off, the green light flashes and I eventually get an error #2 "No acknoledgement". With the radio switched on the green light doesn't flash and I very quickly receive an error #7 "Invalid opcode." Despite this I did try some of the other software functions but I always get the invalid opcode error.

I wondered if my old Toshiba is still too fast for this software so I went into the BIOS and disabled the cache. That didn't make any difference to the programming software though it did make the computer so slow that it takes 20 minutes to load Windows 98 which is now unusable and in the process I somehow managed to set a password which I don't know so I can't get back in to the BIOS to enable the cache again.

I don't have another radio to test the interface with or another interface to test the radio. I did manage to obtain 2 other copies of the programming software besides the one that came with the interface but they all have exactly the same errors with the communication.

I am totally at a loss what to do next and hope that someone here will have some suggestions.

One problem you definitely have is that the W98's so-called DOS is not true DOS. The only way to make a Motorola RSS program run correctly is to boot your computer from DOS 6.22. If you do a search on this Board you will find numerous references to this situation and problem. The serial port of the W98/DOS arrangement is not the same as when running true DOS, hence the problem.

The Maxton unit looks as if it has a RIB built into it. The red LED should indicate power and the green LED should probably flash when data is being sent and received. If this unit is working properly then your problem is most likely in the computer's serial connection and your use of W98 instead of true DOS. You might also try using a pencil eraser on the radio's contacts to improve the circuit between the Maxton and the radio itself. Your Toshiba 1800 should work fine with the GP300 RSS.

Your software may also be corrupted, particularly since you obtained it from an unlicensed/illegal source. For further information about Motorola software, how it is properly obtained, etc. please read the Forum rules.

I changed the startup file so the computer always starts with the text mode menu, so I can boot straight into DOS. I thought that the DOS that comes with W98 is still a real mode 16-bit DOS, essentially DOS 7.0. I will try using an MS-DOS 6.22 boot disc if I can figure out how to make one, the problem being this computer is the only one with a floppy drive and it has no connection to the internet. I'll also try cleaning up the contact on the back of the radio. Thanks for the tips.

What happens with the W98 DOS is that quite often it will allow you to read the radio, but when you attempt to program the radio it won't work at all. And sometimes, depending on the radio, RSS, computer, etc. it won't work either way. You can download the 6.22 from several websites, one of which is http://www.computing.net/answers/dos/do ... 15653.html. Let us know of your progress. I for one would like to know if that Maxton unit works.

Regards,

Tom, thank you very much for your help.

I downloaded an MS-DOS 6.22 boot CD image and burned a boot CD, then used that to boot my Win98SE PC. It would not recognize the hard drive partition created by Win98SE setup so I had to delete it, FDISK and format it, copy the DOS files across and create a config.sys and autoexec.bat that would allow CD-ROM access when booted from the hard drive straight into DOS. I suppose I should have done that in the first place but I actually had the Win98SE disks so I thought that would be easiest. Considering how long the Win98SE setup took it would have been quicker to do that in the first place, but it has been years since I last installed that version of Windows and I had forgotten how long it took!

I reinstalled the GP300 software, configured it to use COM1 and connected the interface, ran the comms test and it said "Radio communication OK!!!" You may have heard the cheers! So I was then able to program the radio with my 2m frequencies, and have just finished two QSOs through the GB3LA repeater using it, so I guess it works!

I used to be a programmer from before the earliest days of PCs, I owned the Ray Duncan MS-DOS programmers "bible", I have even written comms software and I would never have thought there was any difference between MS-DOS 6.22 and the Win98SE version, so it was only your certainty that this would solve my problem that made me actually try it. Thanks again.

Julian,

I'm really glad it worked out for you, and it's also good to know that the Maxton unit works.

Messages such as yours make my day, believe me, so thanks for getting back with the report.

73,

It's too bad I didn't see this thread a little earlier. You could've saved a lot of work by using the "MS-DOS mode for Games with EMS and XMS support" method of booting. It's a shortcut located in the "C:\windows" folder in all Win98SE computers. Drop it onto the desktop & double clicking it reboots you into a far better DOS mode for programming. It'll even continue to boot into DOS after a hard boot. You need to type 'exit' at the prompt in order for it to reboot back into Windows. If you do a search with the terms 'games' and 'support', you'll find many threads over the years detailing this method & the fact it works every bit as well as DOS 6.22 for programming. I've never had it fail me. Just a tidbit for next time!

Todd