1. TAPI Troubleshooting

This document will help guide you through the steps for troubleshooting common TAPI modem questions with WIN-911 Version 7. This article will discuss the following topics

  • How to check if the modem is installed correctly.
  • How to verify DTMF tones
  • Unable to acknowledge alarms over voice
  • No sounds using TAPI with Remote Desktop

A. Scenario 1: Troubleshooting Steps and Verify the TAPI Configuration 

    A.1 How to check if the modem is installed correctly

        1. Verify that you have a direct phone line going into the TAPI modem without converters. Verify that there are no Digital to Analog converters or USB hubs, etc.

        2. Confirmed the modem is listed in Windows Device Manager. You can also open the modem properties and enable logging on the diagnostic tab.

        3. Test the line by plugging in a standard landline telephone to the TAPI line to confirm there is a dial tone.             Make a call to confirm there is no static on the line.

    A.2 How to check for DTMF Issues

  1. If you are experiencing a DTMF issue, in which you don't see any button presses or it is showing the wrong number (E.g. 3 instead of a 4). Then you can resolve the issue with your phone provider or reinstall drivers for the TAPI modem. 
  2. You can confirm if the modem is receiving DTMF tones by examining the log files in Windows Event Viewer or the Modem Diagnostic log in Device Manager.
  3. You can enable Win-911 Debug logging for the Voice Module to determine if the Server is receiving DTMF tones. For more information, you may refer to the How to Turn On Debug logging Article. 
  4. You can test DTMF with standard landline telephone and make a call to an office that will let you press digits to dial an extension.
  5. Check the phone type (iPhone, Android, etc), try it on another phone type and see if the issue exists. 
  6. Make a test call into the WIN-911 system and confirm if you hear the alarm. Verify that you can enter the authorization code and acknowledge the alarm. If you can successfully acknowledge the alarm, then you know DTMF tones are working. If it doesn't work, then try reinstalling the TAPI modem drivers or contact the carrier.

    A.3 If not a DTMF Issue

Trigger an alarm and see if you can ack from the log viewer. If you can acknowledge alarm in log viewer then you need to debug voice. If you can not ack from log viewer then it is potentially SCADA permissions and this will be logged with an error.

There should be a Windows Event log of the issue. Examine these logs to find the cause of the issue, for example, these could be security, SQL permissions, etc. but they will be included in the log. Based on the testing in the previous step, Win-911 will also have a record of what happened and if it is a voice problem.

Another possible scenario is an old alarm that is already terminal that is being called out. This will be available in the WIN-911 log files accessible in Windows Event Viewer.

     A.4 Will WIN-911 work with USB Hubs? 

Yes. WIN-911 will work with Hubs, Digital to Analog (D/A) converters, etc.. This becomes another possible point of failure. When troubleshooting voice issues, it is best to isolate the problem. If possible remove the USB hubs/devices and retest the system to see if the problem persists.

B. Scenario 1: Unable to Acknowledge Alarms With Voice Calls 


With WIN-911 V7, users are receiving active unacknowledged alarms, but when they try to acknowledge the alarm WIN-911 will say, no alarms to acknowledge at this time. A similar message occurs when the user attempts to call into WIN-911 to acknowledge the alarm.


In WIN-911 V7 it is not recommended to configure everyone in the group with the same authorization and access code. TAPI does not know the difference between the name definitions in the group, causing users to be unable to acknowledge alarms. 

    B.3 OPTION 1

To fix this problem, verify each user in the group is configured for a different access code and authorization code.

    B.4 OPTION 2

Users can change authorization codes for a large number of users by following these steps. Create Dummy User to your callout group and change their authorization and access code to different numbers than the original group members. Use the access and authorization code of the Dummy User to acknowledge alarms.

C. Scenario 3: No Sound Using Version 7 TAPI and Remote Desktop

    C.1 Problem

This article is for troubleshooting applications that are using WIN-911 V7 with a Remote Desktop environment and a TAPI modem. When using V7 you are unable to hear anything when you pick up the phone, but you are using a Remote Desktop environment.  

The following error will occur in the Event Viewer logs:

AddTapi: 2018-12-14 09:03:39.64 Cannot obtain ID of wave/out device from call 10333 on line 'MultiMobile MT9234MU CDC-ACM-XR #3', TAPI error 80000042..
AddTapi: 2018-12-14 09:03:39.64 TapiException 80000048, Message='Could not obtain ID of wave/out device for line 'MultiMobile MT9234MU CDC-ACM-XR #3', Wave driver for this hardware is not installed or not configured properly.'
AddTapi: 2018-12-14 09:03:39.64 <MultiMobile MT9234MU CDC-ACM-XR #3> - Could not obtain ID of wave/out device for line 'MultiMobile
 MT9234MU CDC-ACM-XR #3', Wave driver for this hardware is not installed or not configured properly.

The error shows that TAPI is looking for the WAV file that is on the remote machine and not on the local machine. 

    C.2 CAUSE

When making a call using TAPI, the system looks for the Hardware ID of the Wave Driver (Unimodem) when making a call, however, it won't find this file if you're using an RDP session. The default behavior when starting an RDP session is to bring the audio from the host to the RDP client, which breaks TAPI. To fix this issue, you need to change your RDP audio client settings to Play on remote computer under the Local Resources tab. Once you make this change, you will need to reconnect to the WIN-911 system and stop the Telephony service and then restart the WIN-911 Voice Runtime (restarting the Voice Runtime will automatically restart the Telephony service).


Once you make this change, the audio should work.


    1. Open up Remote Desktop Connection and click on Show Options 


    2. Click on the Local Resources tab


    3. Click on the Settings… button


    4. Switch from Play on this computer to Play on remote computer.

Following these steps will allow you to play any audio from a remote computer.

Technical Support

To create a support case, you will need either your Maintenance Support number or your CD Tracking number. You can create a Case online or contact the product support line: (512)326-1011.