Northern Telecom DMS-100 Series Maintenance Manual page 235

A device on the DPP CPU PCA that controls a communications bus between
the DPP processors.
RAM
Random Access Memory
A static, read/write memory system in which information is stored in
discrete, individually addressable locations such that access time is
independent of location.
SIO
Serial Input/Output
Circuitry in the DPP that passes data from the DPP to external devices. The
DPP employs four such circuits in its serial I/O PCA that provides
communications paths between the DPP and DMS-100/DPP maintenance
interface, the DPP EAT, and the remote polling center link (BCS25-28).
DPP Recovery and Routine Maintenance Guide BCS35 and up
List of terms 9-5