Delay in playing a file using dx_playf

Issue

dx_playf, dx_playiottdata functions play back recorded voice data, which may come from any combination of data files, memory, or custom devices. In some cases, the function takes a relatively long time to play a file, or the results show up only after a delay, which may range from 10 to 40 seconds before the other end hears audio. 

Solution Summary

A solution lies either in controlling the resource file or the parameters in the IOTT and TPT tables. 
For a situation where there is no audio at all, check the hardware capabilities.

Technical Discussion

There are several common causes for this issue, depending on the method used in the application. 

1. If Call Progress Analysis (CPA) is used, the event issuing the play function may not yet have been received and processed. In this case the application will display that a play function has been issued, but the play has not actually been started.

2. If the function is waiting for a Call Status Transition (CST) event, check the dx_setevtmsk( ) to see which CST events are enabled. 

3. Check if there may be a delay getting access to the file. If the file is located on a network drive, then it might take longer to access it compared to accessing files on a local drive.  For this reason, it is not generally advisable to play files over the network. 

4. Check the settings in the Input Output Transfer Table (IOTT) and Termination Parameter Table (TPT), particularly if you are playing multiple files or from multiple resources.

5. If no voice is being played, check the hardware capabilities. Verify that the voice devices on the card are not limited voice resources such as those on fax devices.  Limited voice resources cannot be used to play or record files: only Tone Generation and Signal Detection are permitted.