Connecting Rbsu/Rbss Station Devices (Nt-Mode) - Toshiba Strara CTX Series Installation And Maintenance Manual

ISDN Interfaces
In the U.K., the BRI line from the ISDN service provider is a two-wire U-type BRI line. This line
connects to the RBSU TE circuit via a customer-provided NT1 as shown in
necessary to convert the network BRI, two-wire, U interface to the RBSU BRI, four-wire, T interface.
The connection between the NT1 and the RBSU TE circuit is a point-to-point connection, so the NT1
can connect to only one RBSU BRI TE circuit.
A 100-ohm Terminating Resistor (TR) is required at one end of the point-to-point connection. The TR
must be switched into the RBSU TE circuit (refer to option switches in
Table 5-3 on Page
The maximum loop length between the NT1 and the RBSU circuit is 400 meters using CW1308 or 800
metres using CW1700/1750 or equivalent.
RBSU
TE-Circuit
Switch in
100-ohm TR
using RBSU
option switch.
Note: T and U are ISDN standard
reference points.
Figure 5-15 RBSU to NT1 Point-to-point Connection

Connecting RBSU/RBSS Station Devices (NT-Mode)

S-type TAs and TE-1s can be connected to the station side of RBSU and RBSS circuits. TA and TE
devices must be powered by local AC power using AC adapter supplied with the TA or TE device. The
RBSU/RBSS circuits must be configured in the NT mode when connected to TA and TE devices (refer
to option switches in
The TA enables you to connect non-ISDN voice and data devices to ISDN BRI circuits. The TA
matches the protocol of existing interfaces (R-reference point) to the ISDN S/T protocol (see
on page 5-2). TA devices include asynchronous circuit-switched adapters that convert RS-232 sync
data (like data from a PC COM port) to B-channel 64 kbps sync.
TAs also enable you to connect standard telephones and non-ISDN fax machines to receive and make
calls over ISDN circuits. TEs include any user device (telephone, fax, PC video conference board) that
is designed to plug directly into the ISDN (S/T) interface without the use of a TA.
5-18
5-12) and off at the NT1 device or vice-versa.
RJ45 Pinout
(RBSU - BRI jack)
BRI
(four-wire)
3
TX
6
TX
4 RX
5 RX
T
Table 5-3 on page 5-12
RJ45 Pinout
(NT1 - S/T jack)
3
RX
6 NT-1
RX
Switch
in 100-ohm
TX 4
TR.
TX 5
and Table 5-6 on page
Figure 5-15. The NT1 is
Table 5-6 on Page 5-16
BRI
(two-wire)
4 RX/TX
Network
BRI-line
5 RX/TX
RJ11 Jack
U
Demarcation Point
Local AC
Power
5-16).
Strata CTX I&M September 2002
and
5433
Figure