Specifications subject to change without notice. ADTRAN and ISU are trademarks of 
ADTRAN, Inc., 5ESS is a registered trademark of Lucent, DMS-100 is a trademark of 
Northern Telecom, Windows is a registered trademark of Microsoft Corporation. All other 
registered trademarks and trademarks mentioned in this publication are the property of 
their respective owners.
Product Specifications
Network Interface
■ 
RJ-45 for ISDN Basic Rate 
U-Interface or S/T-Interface
DTE Interface
■ 
Two DB-25: each RS-530A/EIA-232 interfaces
■ 
V.35 interfaces available with RS-530A/ 
EIA-232-to-V.35 adapters
Dialing Selections
■ 
Dial Interfaces: two RS-366 interfaces 
■ 
In-band DTE dialing: V.25 bis or AT commands
■ 
Manual or automatic stored number dialing
■ 
DTR assertion
Switch Compatibility
■ 
Lucent 5ESS, NTI DMS-100, NEC
■ 
National ISDN-1
Diagnostics and Testing
■ 
Local and remote loopbacks
■ 
CCITT V.54 Loopback
■ 
Remote configuration
Data Rates (DTE)
■ 
Using single DTE interface:
1200 bps to 115.2 kbps asynchronous 
2400 bps to 128 kbps synchronous
■ 
Dual DTE Interfaces 
1200 bps to 57.6 kbps asynchronous 
2400 bps to 64 kbps synchronous
Data Rates (Network)
■ 
64 kbps (1 B channel)
■ 
128 kbps (2 B channels)
Protocols
■ 
CCITT V.120, T-LINK, SAP, Clear Channel, 
DSU 57.6 Async, BONDING Mode 1, Fallback,
Async to Sync PPP, RFC1717 Multilink PPP
ISU 2x64
Dual Port ISDN Service Unit
ADTRAN, Inc.
Attn: Enterprise Networks
901 Explorer Boulevard
Huntsville, AL  35806
P.O. Box 140000
Huntsville, AL 35814-4000
256 963-8000 voice
256 963-8699 fax
256 963-8200 fax back
General Information
800 9ADTRAN 
info@adtran.com 
www.adtran.com 
Pre-Sales 
Technical Support
800 615-1176 toll-free
application.engineer@adtran.com
www.adtran.com/support
Where to Buy
877 280-8416 toll-free
channel.sales@adtran.com
www.adtran.com/where2buy
Post-Sales 
Technical Support
888 423-8726
support@adtran.com
www.adtran.com/support
ACES Installation &
Maintenance Service
888 874-ACES
aces@adtran.com
www.adtran.com/support
International Inquiries
256 963 8000 voice
256 963-6300 fax
international@adtran.com
www.adtran.com/international
For the regional office 
nearest you, visit:
www.adtran.com/where2buy
Interoperability
■ 
BONDING compatible inverse multiplexers 
■ 
Switched 56 DSUs, ISUs, ISDN TAs, and PPPcompatible routers
Environmental
■ 
Operating Temperature: 0° to 50°C, 32° to 122°F
■
Storage Temperature: -20° to 70°C, -4° to 158°F
■ 
Relative Humidity: Up to 90%, non-condensing
Physical
■ 
Dimensions 
Standalone: 2.25" H, 7.5" W, 10" D
■ 
Weight
Standalone: 3.6 lbs
■ 
Power 
115 vAC, 60 Hz, 
8 watts max dissipation
Product Includes
■ 
ISU 2x64
■ 
7 foot telephone cable (RI45 to RI11)
■ 
User Manual
Ordering Information
Equipment Part #
ISU 2x64 U-Interface, 115 vAC 1200051L1
S/T-Interface, 115 vAC 1200051L2
RS-530 to V.35 adapter cable 1200072L1
Printed in the U.S.A.
61200051L1-8F April 2002
©2002 ADTRAN, Inc. All rights reserved.
ADTRAN is a 
TL 9000 registered company.
ADTRAN is a 
ISO 9001 registered company.