Interoperable Communications

Interoperable Communications

In a world where the confidentiality, integrity and availability of information is paramount, L3 ASA ensures the communication paths are open, reliable, accessible and secure.

Systems provided by L3 ASA offer the widest choice of interface, operating system and communication technologies. Based on L3 ASA’s MultiSwitch communication technology, these high-integrity systems can be deployed in a variety of form factors and environments enabling multiple networks, devices and data systems to interoperate securely in the field.

L3 ASA is a proven provider of mission-configurable, intelligent-switching and interoperability systems, enabling VoIP, circuit switched, radio, and SATCOM networks and devices to inter-communicate. Secure interoperability is achieved through an adaptation to incorporate the majority of crypto devices.

Our Communications Solutions

Communications solutions are available in a variety of configurations, suitable for deployment from datacentre to battlefield.

Our capabilities include:

  • Specialists in Voice and Data Communications
  • Digital, Analog, IP and VoIP protocols
  • Interoperability Gateways
  • Voice and Data Integration
  • Secure Communications
  • Speech Recognition
  • Command and Control Room Communications
  • High Availability (to 99.999%)
  • Interactive Voice Response



At the core of L3 ASA’s communications systems is MultiSwitch, a multi-source COTS component-based interoperability product.

MultiSwitch is a versatile communications application platform that facilitates the integration of application specific characteristics with COTS components. The MultiSwitch architecture allows many combinations of open standards and specialized interfaces to be deployed in a variety of form factors including: ruggedised laptop, 1U PCI / CompactPCI 7U CompactPCI. By making full use of the flexibility provided by working with COTS, systems of arbitrary capacity and complexity can be produced without changing the fundamental framework.  Having the capability to bring together a variety of interfaces and work within the protocol stack, MultiSwitch has the characteristics needed to create interoperability gateways for commercial and military applications. For example, by operating in both tactical and strategic roles it provides an interface between a number of existing and planned military and public communication systems.

MultiSwitch targets include: Microsoft Windows NT/2000/XP/Server 2003/7, Sun Solaris, Linux, QNX, pSOS, and VxWorks. The versatile architecture, coupled with the use of CASE tools, means that MultiSwitch applications can be readily tailored to suit specific project requirements and reduce the time to market.

Our MultiSwitch technology provides the foundation to our solutions for:

  • Interoperability Gateways
  • High-grade, secure communications
  • Legacy and current Crypto Gateways
  • Command & Control Room Communications

Unified Communications is a key requirement and MultiSwitch is the cornerstone for the provision of Interoperability for the UK CORMORANT, GATE, SKYNET and FALCON programmes, uniquely providing a single node to handle the UK TacISDN and NATO STANAG 4578Ed2 protocols.


Depending on the hardware resources available, the MultiSwitch architecture supports the following modes of operation:

  • Two-party, circuit-switched and Voice over IP calls (Voice, Data, and Fax)
  • Voice over IP (PCM / VoIP transcode, H.323 / SIP, Gatekeeper discovery) including Media Conferencing
  • Group Calls (Single- and Multi-homed Conferences, including Intercom and Broadcast) with support for Pressel. Conferences can be effectively sized up to the physical capacity of the platform and can then make use of resources distributed within the network.
  • Traffic transcoding (e.g. PCM/CVSD, STANAG 4213/V.110, STANAG 5000/Group 3 Fax and Fax relay for VoIP)
  • Number translation, between commercial, private, and military numbering plans
  • SNMP-based administration, support for SNMPv2 and SNMPv3
  • Subscriber Location (to enabled networks)
  • 5 levels of Priority and Pre-emption: Routine, Priority, Immediate, Flash, Flash Override (Using the CPI / CPIP and MLPP Supplementary Services, and mapping to DSCP for VoIP media)
  • Packet calls using circuit-switched and IP connections
  • H.450 Supplementary Services (Call Hold, Divert, Forward, Call Waiting)


The capacity of a MultiSwitch application is established by the deployed hardware resources and limited only by the capability of the embedded CT bus. Depending on the selection of COTS items, capacity can range from a few analog circuits, up to more than 2000 digital circuits (in either or both of the E1 and T1 formats) per platform.

Protocols Supported

MultiSwitch has inherent support for numerous commercial and military protocols:

  • Primary rate ISDN and basic rate ISDN
  • QSIG (to ETS 300 172)
  • EuroISDN (to ETS 300 102)
  • DPNSS (to BTNR 188)
  • DASS2 (to BTNR 190)
  • BT-CAS (to SIN 356 Issue 1.0 May 2001)
  • Robbed-bit and NI2 protocols for T1
  • TacISDN (to TacISDN Version 2.2 (DERA/CIS(CIS1)/TR980365))
  • STANAG 4578 (to STANAG 4578 Ed 2 Draft 09/07/02 – enhanced and commercial modes)
  • Voice over IP (to H.232 and SIP, and standard VoIP voice CODECs)
  • Generic HDLC – LAP-B and LAP-D
  • Analog – 2/4 -wire station and subscriber modes, DTMF and loop signalling

Communication Methods Supported

MultiSwitch has support for multiple methods of communication:

  • Circuit-switched voice calls using PCM (G.711 a-law and u-law encoding) or CVSD (encoding)
  • Circuit-switched data calls using I.460 and V.110 data encoding for both synchronous and asynchronous traffic
  • Circuit-switched data calls using NATO STANAG 4213 encoding (to Class 1 and Class 2 formats)
  • Packet-switched data calls using TCP and UDP
  • Voice over IP voice calls using PCM (G.711 or G.729 CODECs)
  • Voice over IP data calls using CODEC to RFC 4040


  • Security signalling based on military protocol
  • Single mode and mixed mode operation
  • Implementation-dependent call security rules

Control and Reporting

  • SNMP v2 / SNMP v3 – including authentication (set, get, and trap)
  • Call and group call logs
  • Diagnostic and error notifications and logs