Toshiba Strata AirLink DK40i, Installation And Maintenance Manual

Page: 664 / 724

ISDN Interfaces
RBSU/RBSS and TBSU Interface Units
16-14
Strata DK I&M 6/00
LEDs on the TBSU and RBSU/RBSS show a continuous status of BRI operation. Refer to Table
16-11 on Page 16-19 for a list of each LED’s status.
Overview
The TBSU, RBSU and RBSS PCBs provide the Basic Rate Interface (BRI) circuits for DK40i and
DK424 or DK424i, Release 4.1. The TBSU can only be installed in the DK40i Base KSU. The
RBSU is the main plug-in PCB that plugs into the DK424 or DK424i cabinet slots and the DK40i
Expansion KSU slots.
The RBSS is an optional PCB that plugs onto the RBSU. Each PCB provides two ISDN BRI
circuits. Each BRI circuit provides 2 B-ch 1D channel for voice/data/video applications.
An REBU PCB is a piggy-back PCB that plugs onto the RBSU and provides basic functions for
RBSU/RBSS circuits so it must always be installed on the RBSU. The REBU is not required on
the TBSU.
The TBSU and RBSU circuits are four-wire S/T type circuits and connect to the Public Switched
Telephone Network (PSTN) BRI lines using an Network Terminator unit (NT1); or, on the station
side, they can connect to ISDN Terminal Equipment (TE) or Terminal Adapters (TA) as shown in
Figure 16-6 .
TE devices include any ISDN device (telephone, fax, computer) that connects directly to S/T
ISDN BRI circuits. TA devices match the protocol of non-ISDN devices (telephone, fax,
computer) to the protocol of S/T ISDN BRI circuits.
The TBSU and RBSU circuits can be configured two ways:
♦ As BRI – TE circuits which connect to Telephone Network BRI lines using a NT1.
♦ As BRI – NT circuits which connect to ISDN TEs or TAs. These devices must be S-type
station devices.
Important!
The DK424 or DK424i and DK40i BRI circuits allocate line numbers and station
ports differently. In DK424 or DK424i, each BRI circuit consumes two line numbers
and two station port when configured as line-side or station side. In DK40i, each
BRI line circuit consumes two line numbers and no station ports; each BRI station
circuit consumes two station ports and no line numbers.
The RBSU connection options (BRI line or ISDN TE-1/TA devices) are selected in DK40i and
DK424 or DK424i customer database programming and option switches located on the TBSU and
RBSU.
The TBSU and RBSU circuits that connect to the ISDN network side requires a dealer-supplied
NTI interface box to convert the two-wire, U-interface BRI line from the telephone network to the
four-wire, T-interface of the RBSU circuit. The NT1 must be UL listed (U.S.) or CSA certified
(Canada). The network BRI line connection is a point-to-point connection, which means that the
network BRI line can only be connected to one RBSU or TBSU circuit via the NT1 (T-reference
point).
RBSS circuits connect directly to S-type TE-1 or TA ISDN devices only. They do not support BRI-
TE telephone network BRI line connections.
The TBSU, RBSU, and/or RBSS circuits that connect to the DK station side, (BRI-NT, S-
reference point) allows direct connection of multiple ISDN (TE-1 or TA) devices. The S point of
the TBSU and RBSU/RBSS supports the Toshiba DK passive bus, also known as point-to-
multipoint connection. The terminal-side (S-point) of the TBSU or RBSU/RBSS BRI circuit can
have parallel connections of up to two TE-1s or TAs maximum.