If your customers want different voices such as welcome whenthe door open, you could upload different voices to doorphones. The importantpoint is these files should be .wav format. Firstly, you log in the doorphoneweb gui and click phone>voice and then select the file which you want to upload. Before you upload the file, you make sure that the file size is less than 200KB and the file format should be .wav. Subsequently, when you click the upload button if the warning which is file uploading success emerges on the web gui, the file has been uploaded successfully. I added a image concerning the steps of uploading.