The DCC-175 Service Manual shows that in the recorder, the cable is connected to the I²S bus that carries the PASC bitstream, and it is also connected to a dedicated serial port of the microcontroller, to allow the PC to control the mechanism and to read and write auxiliary information such as track markers and track titles. The parallel port connector of the cable contains a custom chip created especially for this purpose by Philips Key Modules, as well as a standard RAM chip. Philips made no detailed technical information available to the public about the custom chip and therefore it is impossible for people who own a DCC-175 but no PC-link cable to make their own version of the PC-link cable.