Windows MRCP



Complete documentation for the LumenVox Speech Engine and MRCP Server is available in our online help file


Total Time:
25-55 Minutes

Get Started – Windows MRCP

The Media Resource Control Protocol is a popular way for voice platforms to communicate with speech recognition software. Setting up the LumenVox Speech Engine to work via MRCP is a simple matter of downloading and installing the software and then connecting to our MRCP Server with an MRCP client.

This guide will walk you through installing the LumenVox speech recognition software — the Speech Engine, the License Server, and the MRCP Server — in under an hour. Within 60 minutes, you will have a working sample application able to get decodes from our MRCP Server.

Want proof that it's really this fast?

Watch a timed video of the process, which you can use as a visual aide.

Play Video

Download and Install LumenVox

15–25 Minutes

  1. Open a Web browser and go to and log in with your username and password (email us if you've misplaced it or didn't receive it).
  2. Before you can download your software, you have to deploy it. A deployment is just a group of licenses (or even one single license) that will be on the same machine. To create a deployment, click on Your Account Information.
  3. Click Create New Deployment and assign at least one license to the deployment. Optionally, you may add information like a computer name and a location to help keep track of where you are putting these licenses.
  4. Click Back to Welcome Screen at the top of the page once you have saved the deployment.
  5. Click on Your Software Downloads to be taken to the download page. Download the License Server, the Speech Engine, and the MRCP Server. The Speech Engine is a large file, so it may take a while to download.
  6. Once they have all downloaded, run the Speech Engine installer you downloaded. The installer will walk you through the setup. Once it has finished, reboot your computer.
  7. Now run the License Server and MRCP Server installer applications. You do not need to reboot once they're done.

Installing a License

5–10 Minutes

  1. The first thing you need to do is generate a file called Info.bts that will save some information about your system. Run the License Administrator by going to Start > Programs > LumenVox > Product > License Administrator.
  2. Click Connect and then click Create Server ID File. This saves the Info.bts file to C:\Program Files\Lumenvox\License Server\
  3. Open a Web browser and go to and log in.
  4. Go to your Account Information and find the deployment you made earlier. Click License Upload. Deployments
  5. In the License Upload screen, click Browse, select your Info.bts file, and upload it.
  6. Go back to your account screen and find that deployment — the License Upload link has turned into License Download. Click it and save the LicenseXXXX.bts ( XXXX is a 4–digit number) file.
  7. Back in the License Administrator, click Install License. Select the LicenseXXXX.bts file you downloaded to install it.

Test the MRCP Server

5–20 Minutes

  1. First, make sure everything was installed correctly by going to the Windows Control Panel, pick Administrative Tools, and then Services.
  2. Make sure the following services are running: LumenVox License Server, LumenVox SRE Server, and MRCP Service.
  3. You should now be able to send MRCP requests from your MRCP client to the server and receive back recognitions.
  4. If you don't have an MRCP client yet or if you just want to validate that the MRCP Server is set up correctly, you can use our test client. Click here to download the zip file.
  5. The zip includes SimpleRecognize.exe, a console MRCP client and a grammar called ABNFDigits.gram. This grammar will allow you to decode a string of digits.
  6. You need an audio file for the Engine to decode against. Open up an audio recording utility (such as the Windows Sound Recorder) and record yourself saying the digit string "One two three four."
  7. Before you save the file, you need to set it to be header less (raw), 8–bit, 8–kHz u–law (the standard telephony audio format in the United States). You can do this from inside Sound Recorder by going to File > Properties, and clicking Convert Now... and then setting the format to PCM with the Attributes 8.000 kHz, 8 bit, mono: Sound Selection
  8. Click OK, then save the audio as something like 1234.pcm in the same directory that you extracted the SimpleRecognizer.exe and ABNFDigits.gram files.
  9. Open up a command line (go to Start > Run and enter cmd) and navigate to the directory you saved the files in. From there, enter the following command:
    SimpleRecognizer.exe 554 ABNFDigits.Gram 1234.pcm
  10. It will take a moment to process, and then the server should send back results as an XML string: Windows EXE


Congratulations! You are now able to get recognitions over MRCP. Feel free to try using other audio files or grammars. The syntax for running the simple recognizer application is as follows:

SimpleRecognizer.exe svr_ip_addr svr_port client_ip_addr gram_filename audio_filename

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