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Tektronix CMD80 cellular test set

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Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 Jan 16, 00:41

Hi all,

This Christmas I received a very excellent gift, a Rohde & Shwarz/Tektronix CMD80 cellular test set. It's capable of testing AMPS, NAMPS, TDMA, CDMA, ETACS, JTACS, NTACS, and PCS phones, and it works awesome with my analog phones. It is able to call them or be called by the phones, and the signal it generates reaches at least 50 metres (based on only one test I've done so far) using a 3" piece of wire for an antenna. In addition to sending test tones to the phone, it also has a voice loopback mode in which what you say to the phone is repeated back to the phone, and the test set itself has a speaker which outputs that audio as well, enabling a crude sort of one-way communication. The set also allows you to set such variables as the set's output power, the phone's output power, the voice channel, and so on. It's an incredibly complex machine, and I'll probably never learn to utilize all of the features of it.

I'm going to be demonstrating it on YouTube in three separate videos - an introduction, a brief demonstration video using all of my analog phones, and a full overview/demonstration video. I'll post them here as I make them.

Trent
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Re: Tektronix CMD80 cellular test set

Postby spectreman » 2014 Jan 16, 13:23

Hi Trent.

Very much look forward to your upcoming videos.
The 50m range you get, is this direct line of sight ?
I can get about 100m from mine with some obstacles in the way.
You should try using a higher gain whp antenna with your set.

Cheers, Chris.
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Re: Tektronix CMD80 cellular test set

Postby spectreman » 2014 Jan 16, 13:27

Oh, also Trent, I recently bought a Motorola Tough Talker on ebay, but not the one you were intereted in.
Was a bit cheaper, still expensive enough though.
Waiting for it to arrive.
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Re: Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 Mar 22, 19:13

Hi all,

I've uploaded the first video of the test set. This video involves a brief physical overview of the test set, as well as how I acquired it.

http://www.youtube.com/watch?v=ugZyNWZoTY4

Trent
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Re: Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 May 03, 19:23

Hi all,

The second video of the test set, in which I demonstrate it running with all my vintage cell phones, is now live:

https://www.youtube.com/watch?v=DZ6v0OF63i4

Trent
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Re: Tektronix CMD80 cellular test set

Postby pena » 2014 May 03, 22:29

I suppose I need to add a cellular test set to my "buy when extra cash in my pockets" list... :lol: Most of my phones are GSM or newer, but I have some AMPS phones too.

The test set could really be a modified PC -- I mean, why re-invent the wheel if there's something good enough already out there to be modified. Because we're on a mobile phone forum, good examples are Nokia's two first Communicators, 9000 and 9110: both had 486 processors and ran DOS. Not MS-DOS though.

The phones interfered the video a bit... but did you notice the quiet buzz and no interference on video when the camera was near the old Ericsson at 43 minutes? About 20 seconds earlier video had stripes but no buzz. Oh well, it doesn't matter but I found it strange. :D

Good work! :)
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Re: Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 Jun 01, 00:44

Hi all,

Today I successfully removed the hard drive from my CMD80 (turns out I was trying to remove the wrong part in my previous attempts). And just by looking at the hard drive I've learned a ton about what makes this machine tick.

First of all, the hard drive is a 2.1 GB 2.5" IDE unit, an IBM Travelstar, to be exact. It has a single 500 MB FAT partition - the rest of the drive is unused. Upon connecting the drive to my USB hard drive enclosure, I was able to read it with no problem.

The machine is indeed a PC in disguise. On the drive is a full-blown installation of MS-DOS 5.0. The software that makes the machine tick is simply a set of 16-bit MS-DOS programs. I made an image of the drive (I will never modify the data on the drive itself - it will stay original and I'll continue to use the drive in the machine), wrote the image to a second drive, and deleted the autoexec.bat and config.sys files. I put the drive in the machine, powered it on, and wouldn't you know it - it booted straight to a DOS prompt! I connected an AT keyboard to the keyboard port, and I was able to play around in DOS just like a regular PC. I was even able to start up QBasic and run the Gorillas game! The built-in speaker works as a PC speaker.

I also threw the Microsoft Diagnostics program on the drive. According to MSD, the machine is powered by an Intel 80486DX processor, and has 16 MB of RAM. The display runs on the standard CGA system. DOS also recognizes an A: drive, which I assume is the card reader. Looking in the autoexec.bat file, which contains a ton of plain-english comments, the machines also possibly came with 80386, 80486DX2-50, and 80486SLC processors, and they came with 8, 16, or 20 MB of RAM. Standard units came with 8 MB, and TDMA-capable units came with 16 MB. There was no word on why some units came with 20 MB.

This now afford's a fourth part of my CMD80 video series - a hacking video. I haven't filmed the third part yet, and hope to in the coming weeks.

The biggest fruit of my labor, though, is that for the first time, an electronic copy of the CMD80 operating software now exists. Who knows if Tektronix would service a CMD80 with a failed hard drive today. If they did, it would probably be hundreds, if not thousands, of dollars to do so. Now, if anyone with a CMD80 ever has their hard drive fail, I now have the image. Only thing is, it's 2 GB in size. However, all of the software itself totals only 24 MB, so if someone just wants the software to look at for fun, I might be able to compress the files themselves down to under 20 MB and upload them right on this site.

Trent
Last edited by TheMaritimeMan on 2018 Aug 05, 02:25, edited 1 time in total.
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Re: Tektronix CMD80 cellular test set

Postby spectreman » 2014 Jun 01, 03:33

This is really cool, Trent. Well done. Yes, I would be very interested in a copy of the CMD80 software.
I guess the test set could be made into a dual boot PC, for the test set function & MS DOS mode !
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Re: Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 Jun 01, 04:58

Thanks Chris. Unfortunately, while I was able to compress the files into a small ZIP archive, the site Library won't accept it for some reason. It's only 7 MB in size, so I'm not sure why. I'll ask in the bug report thread.
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Re: Tektronix CMD80 cellular test set

Postby TheMaritimeMan » 2014 Jun 02, 22:22

Got the file uploaded. Here's the link:

http://www.mobilecollectors.net/downloa ... tware_zip-

Trent
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