D630 XFR laptop IO panel USB Ethernet Modem MIC 0d868c board - what is 8 pin plug for?

D630 XFR rugged laptop has different USB / Ethernet / Modem IO board than regular D630 Latitiude or D630 ATG laptops. Part number is 0D868C There are two additional sockets on it. One is used for touchscreen. But I can not comprehend what is second 8 pin socket used for. Please see below photo.