Toshiba Strara CTX Series, Installation And Maintenance Manual, Page: 151 / 290

ISDN Interfaces
5-3
Strata CTX I&M September 2002
RPTU Interface Unit
Circuits per PCB:
30 channels
Interfaces with:
ISDN PRI
Older Version(s):
none
The RPTU provides 30 channels for ISDN PRI service.
The RPTU’s LEDs indicate a continuous status of its operation (see Figure 5-3 and Table 5-2 on
page 5-5 ).
Switches, jumpers, and interface connectors are described in Table 5-1 .
RPTU Overview
The RPTU provides 30 B channels and 1 D channel. Each RPTU can also use its own D-channel for
control.
The RPTU’s in-service bit rate is 2.048 mbps (± 4.6 ppm), but during a maintenance session, the rate
may vary ± 32 ppm.
Extracting the LAYER-1 clock from the ISDN PRI service provider is the most common method used
to synchronise the RPTU PCB and the CT time switch to the public switched telephone network. One
RPTU or RBSU,
must extract the clock from the ISDN provider. The selected unit is designated as the
“Primary” timing source in system Programming. In remote cabinet applications, the Primary clock
source PCB must be installed in the Base Cabinet (main location). For more information, refer to
“Timing and Synchronisation” on page 5-21 .
Slot Assignments
Up to nine RPTU PCBs can be installed in a Strata CTX system providing up to 264 PRI lines
(B-channels). If RPTU (PRI) PCBs are installed, the maximum combined PCBs cannot exceed the
eight. The PCBs must be placed in designated slots in each of the cabinets. Refer to
Chapter 1 – Strata
CTX Configuration , “ISDN PRI Digital Line PCBs” on Page 1-25 , for the guidelines regarding RPTU
PCB slot assignments.
RPTU Installation
Before installing a RPTU PCB into a Strata CTX system, refer to Chapter 1 – Strata CTX
Configuration :
◆
“Strata CTX670 Cabinet Slot Configuration” on Page 1-23
◆
“ISDN PRI Digital Line PCBs” on Page 1-25 (mentioned above in slot assignments)
➤
To install an RPTU PCB
1. Turn the Strata CTX system power Off.
2. Insert the RPTU (component side facing right) into the appropriate slot (see “ISDN PRI Digital
Line PCBs” on Page 1-25 ) and apply firm, even pressure to ensure proper seating of connectors.
3. After installing the RPTU, gently pull the PCB outward. If the connectors are properly seated, a
slight resistance is felt.
Note For cabling information and requirements, refer to “Cabling” on Page 5-6 .