No Audio Input/Output During Voice Call

Hello everyone, thank you in advance for any support regarding this issue.

I’m currently working on a project involving a mangOH Green, a Sierra Wireless WP7504, and the Legato platform. I’m using Legato version 17.07.1, and am trying to write a program that uses the mangOH board to place a voice call. I can get the device placing and responding to calls perfectly fine, but when the call is established, I cannot get any sound to transmit to or from the board. I have a pair of iPhone ear buds with a built-in mic (which, from what I understand, are AHJ/CTIA compatible; I’ve also tried regular headphones) plugged into the CN500 analog audio jack, and I’m using the le_audio and le_voicecall interfaces to establish the call. I’m also making sure that modemService, audioService, and voiceCallService are all running on the WP7504.

In particular, I’m using this example:

I’ve also attempted using the “ATD1234567890;” AT command to dial my phone directly without running an executable, and I still had no luck getting any sound output (or input). I also verified the volume level and mute status via “AT+CLVL” and “AT+CMUT”.

Could there be something wrong with my hardware? I can’t seem to find an answer either way despite searching. Thank you very much for any assistance in advance.