Toshiba CTX28 用户手册

For PRI services, the Strata CTX uses a BPTU or RPTU PCB to connect to a Public Switched 
Telephone Network (PSTN) PRI line using a UL listed (or CSA certified in Canada) Channel 
Service Unit (CSU) in most locations in the U.S. Each BPTU or RPTU provides 23B + D channels. 
The B-channels support CO speech and data connections on the PSTN side only. 

The Strata CTX also uses a BPTU or RPTU2 PCB to connect Strata Net QSIG network nodes 
using DS-1. A DS-1 may be obtained in several ways, most commonly, leasing it from a carrier.

BRI S/T is available with the RBSU PCB. The RBSU provides two BRI S/T circuits to connect to 
the PSTN BRI line using an external UL listed NT1; or, on the station-side, connect to:

•

S-type ISDN telephones and Terminal Equipment (TE-1-S)

•

S-type Terminal Adapters (TA-S) with non-ISDN devices

Each TE-1-S and TA1-S device can support voice and/or RS-232 switched-circuit data as shown in 

. 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 

 and 

. The combination of RBSU and RBSS uses only one slot to provide up 

to four BRI S/T circuits.

Each installed RBSU or RBSS circuit provides a 2B + D connection and uses a system 
capacity of two station ports and two CO lines regardless of the circuit application, even if 
the circuit is not actually connected.

For BRI U services, the RBUU provides two BRI U circuits that connect directly to PSTN BRI 
lines; or, on the station side, connect to:

•

U-type ISDN telephones and Terminal Equipment (TE-1-U)

•

U-type Terminal Adapters (TA-U) with non-ISDN devices

Each TE-1-U and TA-U device can support voice and/or RS-232 switched-circuit data 
depending on the device (see 

). The station-side BRI U circuits are point-to-point.