Toshiba Strara CTX Series, Installation And Maintenance Manual, Page: 149 / 290

Strata CTX I&M September 2002
5-1
ISDN Interfaces
5
This chapter covers information on the ISDN Primary Rate Interface (PRI) and Basic Rate Interfaces
(BRI).
PRI Overview
For PRI services, the Strata CTX uses an RPTU PCB to connect to a Public Switched Telephone
Network (PSTN) PRI line. The RPTU PCB is shown in
Figure 5-1 on page 5-4 .
The Strata CTX also uses the RPTU2 PCB to connect StrataNet QSIG network nodes.
BRI S/T Overview
BRI S/T is available with the RBSU PCB. The RBSU provides two BRI S/T circuits:
◆
S-type ISDN telephones and Terminal Equipment
◆
S-type Terminal Adapters
The station-side BRI S/T circuits are point-to-multipoint.
A subassembly (RBSS) can be attached to the RBSU for two additional BRIs for S-type station-side
connections only. The RBSU PCB and the RBSS subassembly are shown in
Figures 5-9 and Figure 5-
10 on page 5-12 . The combination of RBSU and RBSS uses only one slot to provide up to four BRI S/
T circuits.
Note Each installed RBSU or RBSS circuit provides a 2B + D connection and uses a system
capacity of two station ports and two Exchange lines regardless of the circuit application, even
if the circuit is not actually connected.