Chapter 1: Understanding ISDN and the ISU 512
4
ISU 512 User Manual
61202.086L1-1
ISU 512 INTEROPERABILITY
Telephone networks are evolving from analog technologies to digital technol-
ogies such as ISDN. This transition is time-consuming and costly for tele-
phone companies and upgrading all locations and facilities is a lengthy
process.
The ISU 512 bridges this transition by supporting communications with exist-
ing and future network services and equipment. The ISU 512 supports com-
munications with Switched 56 (SW56) Service and Switched 56 DSUs (2-wire
and 4-wire) as well as various ISDN terminal adapters, ISDN terminal equip-
ment, and BONDING Mode 1-compatible inverse multiplexers.
Figure 1-2 illustrates the ISU 512 (U interface) operation in various switched
network services and customer premises products.
Figure 1-2
ISU 512 (U interface) Applications
The ISU 512 (ST interface) will also support these configurations but will require an
external NT1 for each BRI line.
Bridge/Router
High-speed
workstation
ISDN SWITCH
V.35
V.35
RS-530/V.35
512 kbps
Videoconferencing
•Cost-effective video at 384 and
512 kbps
•Interoperates with
SW56 DSUs and dual port
ISDN TAs at 112/128 kbps
Disaster Recovery - T1 Backup
•TSU with Dial Backup
Module (DBU)
•Up to 512 kbps of backup
bandwidth
High-Speed File Transfers
•Image transfer
•Data backup
ENTER
1
2
3
4
5
6
7
8
9
#
0
*
CANCEL
R S C S T D R D C D T R S R
ISU 512
ISDN SWITCH
ISU 512
ISU 512
Up to 4 BRI U-Interfaces
Up to 4 BRI U-Interfaces
ISU 512
Up to 4 BRI U-Interfaces
ISDN SWITCH
ADTRAN T1 DSU/CSU,
TSU 100, OR TSU 600
T1
ENTER
1
2
3
4
5
6
7
8
9
#
0
*
CANCEL
R S C S T D R D C D T R S R
ISU 512
ENTER
1
2
3
4
5
6
7
8
9
#
0
*
CANCEL
R S C S T D R D C D T R S R
ISU 512
