DataBand ISU 512U - I-Mux Service Unit 512k with up to 4 x “U” BRI ISDN ports

DataBand ISU 512U

The DataBand ISU and CSI range connect high speed serial data devices together using multiple ISDN calls, in effect dialling a high-speed “leased line” between non-ISDN devices. The 512U version is available with 2 or 4 x “U” 2-wire Basic Rate ISDN interfaces (common in North America) and can deliver data rates of up to 512kbps. {There is also a version with both 2 x “U” interfaces and 2 “S” TE interfaces which gives added flexibility if unsure of what ISDN services may be available}. Available with 1 or 2 I-Mux serial ports. The ISDN can be partitioned between the 2 ports or access dynamically so 1 port can use all of the ISDN, for example. This gives a great deal of flexibility on potential speeds of different calls. The Cascade option allows the system to be further expanded.

The ISU 512U supports a single interface to a DTE plus an RS366 dialling port, or one or two DTE interfaces (using a dialling method other than RS366). Ability for I-Mux ports to provide clock or not. This overcomes issues with some attached devices. All units use high-quality internal PSUs and are available with AC or DC inputs. The key-pad and LCD are designed for fast and simple operation of the device with minimal input required to perform the dialling functions. Detailed configuration is achieved via the GUI, which can be connected via the serial port (can be disabled), an Ethernet port (used only for configuration access and can be disabled) or via a remote ISDN call (can be disabled). Various Password levels are available if required. The GUI (DbLite) is free of charge and provides configuration of one unit at a time. The traffic between the Manager GUI and the device can be optionally encrypted via an AES256bit system with key exchange routines. Unlike most other devices, the DataBand has formal Telecommunications Approvals for direct connection to carrier ISDN services.


  • Basic Rate ISDN inverse multiplexer or I-Mux
  • Single or dual high speed serial ports
  • Up to 4 ISDN 2-wire “U” interfaces
  • One or two V.35, RS530, X.21/V.11 interfaces
  • RS366, control lead, front panel or GUI dialling
  • If 2 ports are fitted each can share/contend or all/part of the ISDN
  • Speeds to 512kbps
  • Supports BONDing standard and 64k ‘clear’
  • Option to clock or not clock idle ports
  • Inter-works with other I-Muxes, including Adtran® ISU
  • Interworks with DataBand CSI (Central Site IMux)
  • Intuitive GUI and front panel control
  • Local Management serial port and Ethernet port (can be disabled)
  • Password protected
  • Encrypted Management protocol
  • NV RAM stores configuration
  • Dual FLASH banks for updates
  • New design using latest supportable components
  • Extensive Approvals incl Telecoms
  • Low power consumption
  • RoHS compliant

Typical Applications:

  • Video conferencing
  • Inter-connectivity of encryptors
  • High speed file transfer
  • Aggregation of several satellite links
  • Leased line backup

Application Examples:

1. Standalone Use - The I-Mux capability, using industry standard BONDing algorithms, aggregates the individually dialled and routed ISDN channels, re-ordering them and handling the differential delays between all of the ISDN calls.

DataBand ISU 512U diagram 1

2. Inter-Connection of Encryptors - ISDN on-demand access for V.35, RS530 and X.21/V.11 encryptors RS366 dialling ability.

DataBand ISU 512U diagram 2

And/or stand-alone to CSI Central Site I-Mux

DataBand ISU 512U diagram 3

3. Video-conferencing (VC) - ISDN access for non-ISDN video-conference units. Inter-operates with VCs with internal ISDN ports and BONDing aggregation. Dual-port version gives access to two attached devices, each sharing the ISDN at the same time, or using all the ISDN for one device.

DataBand ISU 512U diagram 4

4. High Speed File Transfer - Dial up high speed access when needed.

DataBand ISU 512U diagram 5

5. Leased Line Backup or Disaster Recovery - Dial backup capacity when needed, via an independent network.

DataBand ISU 512U diagram 6

6. Share ISDN access - When 2 ports are configured, each port can potentially use all ISDN access or the ISDN can be pre-apportioned. This gives the flexibility of having different speed calls on each interface at different times to match the application requirements.

DataBand ISU 512U diagram 7

7. Optional Cascade Port - A separate port allows another DataBand ISU to be inter-linked and to share the same ISDN access. Select an appropriate second ISU, a 512U for example:

(A) An ISU without ISDN to gain extra DTE ports or RS366 dialling port and sharing the primary unit’s ISDN access:

DataBand ISU 512U diagram 8

(B) Use a second DataBand ISU 512 (either with “U” or “S” interfaces) to gain extra DTE ports and extra ISDN ports. Extra ISDN ports can be shared between both ISUs and different ISDN services (“U” or “S”) can be utilised, perhaps for resilience and flexibility:

DataBand ISU 512U diagram 9

(C) The cascaded unit and the combined “S” and “U” variant means the 2-wire “U” interfaces can be shared by local 4-wire “S” interfaces. The network ISDN can be shared between different types of equipment. This also adds a level of resilience:

DataBand ISU 512U diagram 10


A. Network Interfaces

  • Two or four 2-wire “U” NT interfaces (connect to a carrier-delivered service). Dual port versions are field upgradeable to four ports via software key.
  • Version supporting 2 x 2-wire “U” and 2 x 4-wire “S” interfaces. “S” interfaces are user switchable between TE and NT. NT requires a crossed cable.

B. DTE Interfaces - Up to two factory-fit cards available. Any combination:

  • V.35 “MRAC”
  • RS530 25-way “D” – Adtran compatible
  • X.21/V.11 15-way “D”
  • RS366 dialling port 25-way “D” - Adtran compatible

C. LCD/Front Panel

  • 2 x 16 character LCD
  • 16 button key-pad

D. Out-going Dialling Options

  • GUI
  • Control lead - pre-stored
  • RS366
  • Front key-pad/LCD
    • Password protected
    • Pre-stored numbers
    • Manual entry of number(s)

E. In-coming Call Options

  • Accept all
  • Accept authorised (CLI)
  • Manual accept
  • Reject all

F. Data rates: 64kbps to 512kbps per data port (BONDing). 64kbps 'clear'
G. Inter-operability: BONDing compatible devices, including inverse multiplexers
H. ISDN switch compatibility: National 1 (USA), 5ESS, DMS100, Euro-ISDN
I. Power:


  • Internal switch mode supply
  • Standard IEC connector
  • 96-240VAC auto-sensing
  • Max current consumption 100mA @230VAC


  • Internal supply
  • Standard 4mm Terminal Block
  • -33 to -75 VDC
  • 0.35A max consumption

J. Non-Volatile Memory: Configuration held in non-volatile FLASH memory

K. Physical

  • 292w x 200d x 44h
  • Metal chassis, front & rear panels
  • 1.4Kg/2.4lb
  • Optional 19" Rack Mount Kit

L. Environment

  • Operating 0º to 55ºC
  • Natural convection cooling
  • Humidity 10-90% non-condensing

M. Maintenance: There are no serviceable parts or maintenance required.
N. Approvals

  • CE marked
  • IEC60950-1:2nd Edition
  • ACS/NZS60950:1:2011 (IEC60950 and ETSI telecoms safety standards. Suitability to the latest interim ACMA telecoms safety requirement cannot be guaranteed - external primary surge protection may be required. Check specific local carrier compliance requirements.)


  • FCC Part 15 Class A
  • EN55022:2006 - A1:2007
  • EN55024:1998-A2:2003
  • EN61000-3-2:2006
  • AS/NZS CISPR32:2001


  • TBR3/TBR4
  • AS-ACIF-S031 and S038
  • CS-03 Canada
  • TIA-968-A USA


  • Compliant

NB: Replacement for the Adtran 512

Live Demo of FRM220 Chassis

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