Introduction
555-230-024
1-14 Issue 5 January 1998
The main configurations are:
1. Basic system consisting of a Processor Port Network (PPN) o nly.
2. Directly-connected system consisting of two Port Networks (PNs): on e
PPN and one Expansion Port Network (EPN) connected directly together.
3. Directly-connected system consisting of three PNs (one PPN and two
EPNs) connected directly together.
4. Center Stage Switch-connected system consisting of up to 15 EPNs
interconnected by one Switch Node (SN) to the PPN.
5. Center Stage Switch-connected system consisting of up to 21 EPNs
interconnected by two SNs to the PPN, and up to 43 EPNs interconnected
by three SNs to the PPN.
Direct-Connect Configurations
Direct-connect configurations have these distinguishin g characteristics:
■Every port network is connected to every other port network via an
expansion interface circuit pack and a fiber optic cable.
■Each fiber is connected to a fiber transceiver that can transm it great
distances.
In large systems, a port network can be hundreds of kilometers away from the
central site. These remote port networks are connec ted to the other port networks
via a Digital Signal Level 1 (DS1 — T1 or E1) link attached to a converter board,
which in turn is connected to the expansion interface. The converter board con-
verts the fiber optic signals between DS1 protocol and the int ernal expansion
interface protocol so the signal can travel over dedicated public or private lines.
Center Stage Switch Configurations
Center Stage configurations have these distinguishing characteristics:
■An expansion interface in every port network is connected to a switch
node interface in the Center Stage Switch.
■Remote Expansion Port Networks require T1/E1 Converter pairs at the
remote end and switch node T1/E1 Converter pairs at the switch node. In
the pairs, the T1/E1 Converter board converts the fiber optic si gnals
between T1/E1 protocol and the internal expansion interface protocol so
the signal can travel over dedicated public or private lines.
■Switch node interfaces and fiber optic cables are also required for
communication between switch node carriers. The number of switch no de
interfaces required depends on the call traffic between port networks
whose switch node interfaces reside in different carriers .