Upper electronic module
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
The upper electronic module (4/70) transmits information via the Control area network (CAN) to the central electronic module, about which button on the remote control is depressed and the status of the siren.
The central electronic module in turn sends information to the upper electronic module via the Controller area network (CAN), if the siren must be activated. The upper electronic module transmits information via serial communication (Volcano Lite) to the siren control module, which activates the siren.