Sony PCV-R553DS - Manual (Page 81)

System Board 67
AUX-IN Connector
The AUX-IN connector on the system board is a 1 x 4-pin header
connector that connects to the CD-RW drive’s audio output connector.
AUX-IN
Pin Signal Name
1 Left Line In
2 Ground
3 Ground
4 Right Line In
KY0062B.VSD
AUX-IN
1
3
2