The Legato Telecommunications Interface is a product developed by Octave Labs.  Legato provides electrical test circuits such as feeding bridges, artificial lines, and reference impedances required for regulatory and R&D telecommunications testing.  
Legato is distributed world-wide by Listen Inc.  You are welcome to visit the Legato product page at Listen Inc. for more information or download the Legato PDF Brochure if you are interested in Legato for telecommunications regulatory and R&D testing.
As an example of what Octave Labs can do for your organization, here are a few of the techniques employed to develop Legato:
  1.  3D CAD Studies and PCB Design
Utilizing 3D CAD, feasibility studies are performed to discover how to best package electronics and chassis mounted components.  Design factors such as mechanical function, thermal performance, ease of manufacture are taken into consideration.  This study was used to size the Legato motherboard PCB.  Two of the eight peripheral PCBs are shown in the backplane, in this case one feeding bridge card and the reference impedance card -
  1.  Custom Sheet Metal Development
Once the PCBs are sized, components that pierce the sheet metal - such as connectors and mounting holes - are placed on the PCBs.  Custom sheet metal parts are designed to accommodate the PCBs, connectors, controls, and chassis mounted components.  This CAD rendering shows the Legato chassis with the front panel and covers removed -  
  1.  Fabrication and Electronic Packaging
3D CAD models for the custom sheet metal parts instruct fabricators how to manufacture the parts.  Legato’s custom sheet metal is laser cut and formed.  This assures an excellent fit and repeatability.  Exposed parts are powder coated - glossy for the front and rear panels, a tough textured finish for the other parts.  This  CAD rendering shows all of the Legato PCBs installed in the chassis -
  1.  USB Control, Firmware, and Software Development
The custom USB interface and firmware allows communication between a PC and the Legato.  An API allows electroacoustic test software to control the Legato directly.  This allows Legato to be integrated with electroacoustic test platforms.
  1.  Legato Technical Information
Legato provides a feeding bridge, reference impedances, adjustable battery supply, a precision artificial mouth amplifier, and other circuits.  These are required for testing analog telephones, speakerphones, conferencing systems, PBX systems, voice gateways, line cards, and other telecommunications equipment.
Legato’s low noise measurement system galvanically isolates the electroacoustic test system from the device or system under test.  Option cards can add more functions, such as a second feeding bridge, country specific artificial line banks, and a DC measurement and control system.  Regulatory reference circuits required for TBR38, TIA-470, IEEE 269, and IEEE 1329 are also offered.  Legato can be customized for your specific needs.
Listen Inc.’s Legato product page has detailed information if you are interested in Legato for your regulatory or R&D telecommunications testing, or download the Legato PDF Brochure here.
Le·ga·to: in a manner that is smooth and connected
© 2009 Octave Labs, LLC
Legato Telecom Interface