Examples of C-cables
WARNING: This page is about a different car, the 2003 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
The BCM communicates with the alarm siren module (ASM) and alarm sensor via a C-cable.
The CIM communicates with the ignition switch module (ISM) and steering column lock (SCL) via C-cables.
The ACM and front and side sensors communicate over C-cables.
The ICM communicates with the SID and SIDC via C-cables.