VW CARE

Hello i have an 07 QT 4.2L my friend replace the battery and after a couple of days after, the MMI stop working, i checked fuses and there are ok i think, using VAG-COM performing optical ring test the voice control module present malfunction, electrical and optical and telephone control optical only, i would like to know where the voice control, control module is located to connect a fiber optic loop to proceed with my diagnostic if you guys please help me i would be thankful