Sunday, 8 July 2018

Rohde & Schwarz CMU200 Universal Radio Communication Tester resources

Rohde & Schwarz CMU200 Universal Radio Communication Tester resources


This post is a collection of information for the Rohde & Schwarz CMU200 Universal Radio Communication Tester that I have purchased. They can be bought on eBay and other places often for a very reasonable sum. In its day it was an expensive but capable instrument.

While the CMU200 is primarily designed for testing now obsolete mobile phone equipment, it can be used for working with analog radio. It has a spectrum analyser, RF generator, RF power measurement and with the option, an audio test set. While not directly having a tracking generator function, there are two PC programs that allow it to be used for testing filters. It can also be done with a noise source or an external tracking generator.

The CMU200 uses an embedded Celeron or similar AMD processor running MS-DOS. It has an internal IDE HDD that is wise to replace as the instrument can do tens of thousands of hours. An IDE SSD allows the instrument to boot much faster.

Documentation is available from R&S. The CMU200 is discussed often in the eevblog forum.

The CMU200 can be used with a PC via a GPIB USB adaptor. There is R&S and third party software that increases the instument's functionality.

I have compared a duplexer response with the CMU200 and Siglent SSA3021Z with a $20 noise source and the Siglent's tracking generator.

My machine while replacing HDD, yes that is it on the top. The screen is dimmed around the edge presumably from curling of reflector around fluro tube. Will fix/replace. Screen is spectrum analyser showing local DVB-T TV stations. Nice!


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Replace HDD with SSD

My analyser had its original HDD c2000 with 35000 hours. As such I was keen to back it up and replace it. No trouble extracting HDD or backing it up. I unsuccessfully tried the Kingspec drive as per below, but the drive was not recognized. I did the same with an old 20GB HDD from a laptop and that worked fine. My analyser uses earlier AMD CPU and older BIOS. That may be the difference? Cute using PS2 keyboard on an instrument to do MSDOS.

cut and paste from eevblog forum in italics

"The HDD-Raw-Copy-Tool tool does a sector by sector copy of the entire drive. The resulting RAW image can be opened by a tool like PowerISO and this what I used to upgraded the CMU200 DOS software.

Both the CMU200 Celeron and CRTU-RU Pentium III boards have worked with various Fujitsu 20GB and IBM 30GB IDE drives I have connected.  BIOS has autodetected all OK. I have replaced the CMU200 drive with Kingspec PATA IDE 2.5" 32GB SSD and again HDD-Raw-Copy-Tool was used to write the image to the drive before installation. Now the CMU200 boots like a rocket.

I note the Award BIOS FLASH tool and bios image can be found in \internal\install\bios folder. Run the batch file FLASH.BAT to reflash."

"1) remove the hard drive from the CMU, and attached is to a device like this:

2) made an exact image of the drive to a file with this software: (I used the portable version to avoid installing the software)

3) removed an IDE harddrive from a back-up USB drive I had lying around (the HD in my CMU was a 20GB one, but I replaced it with a 40GB one without any issues

4) restored the image from the file to the "new" HD using the same software as in step 2"

Screen fix: LCD & EFI glass

LCD fix or replace

The screens can fail or go dim. A dim screen seems to often be just the reflector curling around the tube. The tube back-light can be replaced with LED strip.
Detailed fix:

It seems possible to replace the screen with a new one. The screen seems to be a Sharp LQ084V1DG21  They are on eBay for US$100+. I have ordered one and will replace it when it arrives, with a report here. Main trouble with mine was EFI glass.

Graphic LCD Display Module Transmissive Red, Green, Blue (RGB) TFT - Color Parallel, 18-Bit (RGB) 8.4" (213.36mm) 640 x 480 (VGA)

EFI glass

The EFI glass commonly discolours. It was the main problem with my CMU200. Removing the glass fixed the problem, but getting a replacement EFI glass is a problem, but looking. The screen is still a little dim and I will replace it.


Operating, quick start and service manuals:

manufacturer page:

and the brochure:

Detailed specifications:

Service manual:



Only the most recent firmware seems to be available from R&S. Earlier versions seem to have expired. Probably a good idea to keep a copy of current firmware before updating. May be a good idea not to update if little extra functionalityis added. See firmware text file for earlier versions.

CMU200 last firmware downloadable via R&S GLORIS account (picture is screen shot from GLORIS not links). Other links are below.

Base 5.21 firmware
CDMA 2000 MS 5.20 package is here : - manual - install - It is PC part of CMU-K92 option, GPRS application testing package. Manual is also there.

All new firmware?

Text file from eevblog?

R&S software

CMU200 Software- CMUgo- Remote control software


The free software FreRes from Rohde & Schwarz allows to make sweep and test for example filters or duplexers.

Third Party software

My unit

Serial Number: 10133X, X=bd-23
CMU-B11 (HW): Reference oscillator OXCO, aging 2 X 10E-7/year
CMU-B12 (HW): Reference oscillator OXCO, aging 3.5x10E-8/year
CMU-B21 (HW): Universal signalling unit CMU-B21V14 incl. CMU-B54
CMU-B41 (HW): Audio Generator and Analyzer
CMU-B83 (HW): CDMA2000® signaling unit (requires R&S®CMU-U65)
CMU-U65 (HW): Upgrade kit for CMU200: Measurement DSP module for measurement speed improvement
CMU-K29 (SW): Analog AMPS, for CMU-B21, CMU-B41 required V5.20
CMU-K84 (SW): CDMA2000 (cellular band) for CMU-B83 V5.20
CMU-K85 (SW): CDMA2000 (PCS band) for CMU-B83r V5.20
Front Module: FMR5
Memory: 128 MB
Firmware: V8.50 02.05.06

Duplexer tuning

A duplexer response with the CMU200 and Siglent SSA3021Z with a $20 noise source and the Siglent's tracking generator, respectively. The tracking generator is best, not surprisingly, but the noise source with the CMU200 is quite usable. Adjusting for insertion loss would be awkward. A noise source avoids needing a PC to run the tracking generator in the CMU200.


  1. How could you ever be disappointed with a rohde-schwarz. Half the fun is learning all the features.

  2. Yes, they are a great bit of gear. Certainly a lot of features. Part of the point of the blog post is to document things so I can find them again.

    I have just imaged another HDD and put it and a copy on DVD in the machine so there are always two copies.