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Liberator S

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Liberator S ISDN Converter, Splitter, Switch & Concentrator

Liberator S

The Liberator S ISDN Converter, ISDN Splitter, Switch, and Concentrator supports up to 4 E1/T1/PRI interfaces and 0, 4, 8, 12, or 16 BRI ‘S’ interfaces. As standard Liberator ‘S’ can be user configured with either all E1 or all T1 PRI interfaces. Purchasing the optional E1/T1 conversion pack means both E1 and T1 can be supported on the same unit. BRI NT and TE ports can optionally be fitted with Power Failure Relay Protection. BRIs can be set for ETSI (Euro-ISDN) or ANSI (US-ISDN) on a per-port basis and can perform ANSI to ETSI conversion. The unit will connect any port to any port and any ‘B’ channel to any ‘B’ channel without constraint giving full cross-connectivity between all ports, both local and network channels. The intuitive DbLite GUI (supplied) enables fast and simple configuration. All options can be set to tailor the use, connectivity, least cost routing and other advanced features to match the requirements. The flexibility and modularity of the Liberator means it can be put to many varied uses.


  • Very flexible PRI/BRI ISDN switch
  • ISDN splitter, sharer or concentrator
  • Converts between PRI and BRI
  • Connects to ISDN networks and/or local ISDN devices
  • Shares ISDN access between multiple local devices
  • Full cross-connection between any/ all ‘B’ channels
  • BRI Power Feed options
  • Least Cost Routing
  • Dynamic re-directing of calls if destinations unavailable
  • Local connectivity between any ports
  • Build multiple BRI networks ports into a local PRI
  • NT BRIs and optionally NT/TE user switchable
  • BRI Power Failure Relay Protection option
  • PRI ports NT/TE user switchable
  • PRI ports Power Failure Relay protected
  • Standard ETSI to ANSI PRI to BRI conversion
  • BRI ANSI to ETSI conversion
  • Optional PRI E1 to T1 conversion
  • Supports A-Law to μ-Law for voice conversion
  • Support for “Call Deflection”
  • Tones generated from network and/or by Liberator
  • Different models available to support different I/O combinations
  • Field-upgradeable versions to remotely enable additional ports
  • Remotely manageable and software upgradeable
  • Off-line Call Routing configurator

ISDN Services
- Signalling is carried/converted between ports and ISDN types including when converting between ETSI and ANSI standards. Supplementary Services from the network are passed transparently to local devices. Sub-addressing handling and routing is supported, as is the ability to route on Bearer Capability (call type). CLIs can be locally generated and SPIDs (US - based BRIs) are supported.

Configuration/Management - Liberator is configured and managed by DbManager which is an intuitive GUI which supports multiple real-time workstations and is the common platform for all Liberator & PacketBand products (see below). Versions are available which can be configured for the smallest installation, or up to many thousands of devices. Configuration/management sessions can be established remotely via an ISDN call or locally through the unit’s LAN/Ethernet port or the RJ serial port. SNMP Traps & Alarms are supported as is a call analysis tool.

Liberator S DbManager

Ports, inter-connectivity and routing:
Ports, Channels and Groups
- Liberator employs a simple system where BRI and PRI ports or individual ‘B’ channels can be allocated to one or more customer named “Groups”. These Groups form the basis of all configurations, making it fast, simple and intuitive to your applications. As an example you can refer to a Group of 4 BRI ports as ‘Video 1’ and subsequently use this term on all routing parameters. ‘Hunt Groups’ or ‘rotaries’ are as easy to establish.

Call Routing - Calls can be routed on the number dialled, the sub-address, CLI, Call Type, originating port, time-of-day or a combination of the above. Whatever your routing requirements; Liberator can help.

Cross-Connection - Any ‘B’ channel can be connected to any other within Liberator without constraints (unless some are programmed). Any port can be barred from calling any other port or number. Any call can be routed to a Group of ports or 'hunt-group’. Multiple devices can be configured to accept calls dialling to a range of numbers and the calls can be routed to a Group in a variety of ways (sequential, always the lowest available port etc).

Redirection on ‘Busy’ or ‘Unavailable’ - Incoming calls can be automatically rerouted to alternate preprogrammed numbers, groups or ports if the main number or port is unavailable. This gives the ability to automatically switch to backup or standby device for resilience purposes. Liberator supports a Secondary and Tertiary destination or Routing Profile. If an out-going call to the ISDN network cannot be established (user or network busy, for example), Liberator can automatically redial via other network ports without the end user having to take any action. The same can be done for incoming calls switching between local devices.

Call Deflection - Some carriers support the “Call Deflection” service. With Liberator calls can be automatically diverted to a different destination, without using any local ISDN channels, based on a number of criteria including DDI number, time-of-day, and/or no answer.

E1 to T1 Conversion - Liberator can optionally convert between E1 and T1 PRIs. Note that as standard Liberator converts between any PRI type and any BRI type (ETSI/ANSI). Liberator supports the necessary A-Lau to μ-Law encoding conversion necessary for voice traffic.

Nailed Calls - Timeslots or ‘B’ channel capacity can be established on behalf of devices which are unable to handle dialling protocols. For example, Liberator can provide capacity for non-switched Fractional E1 and T1 circuits. These ‘Nailed’ calls can be configured as temporary or permanent, giving the ability to profile capacity to match needs.

Channel Reservation and Scheduling - This features has the ability to change and structure profiles in an efficient way and to vary them if your routing or capacity requirements change during the day or week. Time-of day - A Group can reserve a number of channels based on the time of day. A Group can also be configured to have a Minimum and Maximum number of destination channels available and reserved for the Group’s use. This facility gives flexibility when allocating network access to different devices, allowing each to have a reserved minimum capacity available for immediate use. Setting the maximum capacity means the ISDN devices can share and contend for the remaining ‘B’ channels yet any device cannot take an unfair proportion. The Maximum and Minimum access rates can be varied based on day and time. Up to eight different profile schedules can be configured per Group. If any schedules overlap, a warning is given.

Least-Cost-Routing - A number of options are available to assist with selecting the best route. Calls beginning or ending with particular numbers can be routed to a specific Group or ‘B’ channel. Additional Ports can be configured as secondary/tertiary destinations should the preferred Port(s) be busy or unavailable. Liberator has the ability to convert or translate any incoming or outgoing number into any other number, to add/remove leading, middle and trailing digits.

Number Translation or Conversion - Any incoming dialled number can be converted by Liberator and presented on any ISDN interface. For example an incoming call to 12345 may be converted to 98765 because the original extension at 12345 has moved onto a VoIP gateway on a different ISDN PRI and now the users has a different DDI number. Liberator can  convert/add/delete leading digits, digits in the middle of numbers and/or trailing digits. It can also manipulate sub-addresses and CLIs. All of this flexibility is not required by all, but if you should need it, it is easy to use and configure.

Tone Generation - Liberator normally passes the tones transparently between ISDN points but this is not always possible in all instances, such as some least-cost routing applications, if there is no network at all, or in certain other circumstances such as when Liberator cannot make a final routing decision until the number is dialled. In these instances, Liberator can be configured to generate dial, ring, busy, N/U tones itself.

CLI Generation - Liberator is able to generate a CLI field. The number of the CLI can be programmed for individual ports or calling numbers.

Power Feed (Phantom Power) - Some ISDN devices do not have a power supply and are powered through the BRI interface. Liberator optionally supports Power Feed for BRI NT interfaces. This must be specified at the time of ordering and cannot be retrofitted.


PRI/E1/T1 - 1, 2, 3 or 4 PRI ports.
Marked as ‘PRI21’ ‘PRI22’ ‘PRI23’ and ‘PRI24’. By default PRI21 and PRI23 are configured for TE ISDN stack (user-side); PRI22 and PRI24 for NT (network-side). The default configurations can be changed by the user but crossed cables are necessary. Interfaces PRI21 - PRI22 and PRI22 – PRI24 are protected against power failure by relays which provide a metallic path in the event of failure.

  • RJ45 120Ohm balanced (E1)
  • G.704 HDB3 encoded
  • Auto-detect CRC4 or non- CRC4 framing (Multiframe or Doubleframe)
  • Support of non-switched E1 and Fractional E1 services
  • ISDN PRI ETSI Q.931/921, ETSI-DSS1, ETSI 300-011, ETSI300-125, ETSI 300-102, approved to TBR4
  • A-Law and μ-Law tones


  • RJ45 100Ohm balanced T1
  • ESF or D4 Framing selectable
  • B8ZS or AMI Line code selectable
  • NI-2, DMS-100, AT&T 5ESS Switch selectable
  • AT&T TR-62411 and ANSI T1.403 Compliant
  • Hong Kong variant available
  • A-Law and μ-Law tones

BRI 0, 4, 8, 12 or 16 Ports (depending upon Model)

  • Field-upgradeable versions available.
  • Marked as ‘BRI1’ through to ‘BRI16’
  • RJ45
  • 4-wire S0 compatible
  • Configured as NT but optionally user-switchable in blocks of 4 ports to TE mode (requires crossed cables)
  • Blocks of 4 NT and 4 TE ports can be optionally Power Failure Relay Protected which means the two ports are linked via metallic path in the event of power loss so the attached device(s) still have network access. BRIs can be user configured for US and ETSI on a per port basis. Can be configured for Point-to-Point or Multipoint. SPID settings for US-based applications.
  • Support for NI-1, DMS100, AT&T 5ESS and Auto Single and Dual SPID configurations.
  • Driving distance on UTP CAT5 cable typically up to 750m depending upon DTE and environment.
  • Optional Terminal Power-Feed with external 40VDC supply for NT ports. Provides 40V 1W to ISDN BRI devices which do not have their own power supply.

Control Ports

  • RJ11 Marked ‘Cmd’ - Asynchronous 8 data, 1 stop bit no parity 19.2kbps to 115kbps
  • Password protected
  • Dry contact alarm relay

PRI x 4

  • Each PRI has 2 associated LEDs
  • Upper LED - fl=synchronising to Layer 1; solid=Layer 2 established
  • Lower LED - fl=call establishing; solid=at least 1 call in place


  • Each BRI has 2 associated LEDs, 1 for each ‘B’ channel
  • Fl=call establishing/dialling; solid=call in place

PWR x 1: Unlit=no power; Green=power on unit
Run x 1: Slow flash=microprocessor OK and configured; fast flash=internal error or lost base configuration
LAN ACT x 1: Activity on the LAN
LAN 100 x 1: Off=LAN running at 10baseT; on=LAN running at 100baseT

Interfaces pairs PRI21 and PRI22 and PRI23 and PRI 24 are Power-Failure Relay protected as standard. Blocks of 4 NT and 4 TE BRI ports can be optionally Relay protected. Factory fit. Interfaces will be connected together using relays in the event of power failure. This forms a metallic path between the two ports.

1. Mains - AC

  • Internal switch-mode supply IEC connector
  • Voltage range 95-240VAC autosensing
  • Input frequency 47-63Hz
  • Max current consumption 200mA @ 230VAC

2. Optional for Power Feed - required for non-powered attached user devices

  • In addition to AC power
  • External in-line supply
  • 2.1mm jack
  • Voltage range 90-264VAC
  • Input frequency 47-63Hz
  • Current consumption 700mA @230VAC
  • Max DTE draw 1W @ 40VDC

3. DC -48VDC nominal

  • 4mm terminal block
  • -33VDC to -75VDC
  • 0.35A max
  • MTBF 179,000 hrs

4. DC -24VDC

  • 4mm terminal block
  • -18VDC to -75VDC
  • 0.55A max
  • MTBF 800,000 hrs


  • Operating 0 – 55 °C
  • Humidity 10-90% non-condensing
  • Natural convection cooling


  • 292mm wide x 200mm deep x 44mm high
  • Metal chassis, front and rear panels
  • Weight is 1.1Kgs 2.4lb
  • Optional 19’ rack-mounting kit

There are no serviceable parts or maintenance required. The battery used for the real-time clock and some NV RAM elements has a 10 year (typical) life-time.

All approvals completed in UK

  • TBR12/TBR13
  • TBR4:1995, 1997 Amendment
  • TIA/E1A-IS/968
  • TNA117
  • AS-ACIF-S006/S016
  • CS-03 Canada
  • TIA-968-A USA


  • EN55022:1998
  • EN55024:1998
  • A12001
  • EN61000-3-2/3:1995
  • AS/NZS CISPR22:2000


  • IEC60950-1:2007
  • ACS/NZS60950:2000
  • AS/NZS3260:1993
  • ACA TS001:1997