Voice over IP and IP Media Streaming

A recent NHT Design Solution required an innovative approach to develop hardware and software for an integrated Voice over IP (VoIP) and IP multi-media streaming module. The solution was required to enable two-way (full duplex) voice communications channels on demand between call terminals and a remote monitoring point, whilst also providing continuous audio streaming from a media server.

Key requirements for the design were:-

Low Bill-of-Materials Cost
Low Power
Small Form Factor
Rapid Time to Market
Compatibility with off-the-shelf SIP-based VoIP products
Compatibility with off-the-shelf media streaming products

The NHT Design Team developed an integrated System-On-Module (SoM) design to meet the product requirements. The module was designed to be compliant with industry standards, allowing it to be connected to other system and external 3rd party components in a 'plug-n-play' fashion. To keep costs to a minimum, industry standard technologies, such as Double Data Rate (DDR) system memory, were implemented which, through their use in other areas such as the commodity PC industry, enabled the associated economies-of-scale to help produce a design within budget requirements.

Key to the software development was use of Linux as a development platform. This enabled rapid progression through prototyping and testing, due to the wide range of Linux support and software available, and allowed a scalable software platform to be developed. This software was based on solid open source libraries, whilst maintaining specific proprietary software, through use of special multi-use licensing such as the Lesser GPL license.

Our Embedded High-Speed Digital Design Team produced a versatile, modular design with the following hardware features:-

240MHz Freescale Coldfire CPU
Compact Modular Form Factor (80 x 50mm) with Low Impedance Connectors
USB Host Support
32MByte DDR2 SDRAM and 4MByte NOR FLASH Memory
I²C and SPI Communications Support
10/100 Mbit/s IEEE 802.3 Ethernet Connection
Loudspeaker and Headphone Audio Support
Impedance Controlled 8-Layer PCB Layout
Design for Manufacture (DfM) and Signal Integrity Simulation

Our Embedded Software Specialists produced a scalable, modular, flexible platform software solution using highly stable and functional Open Source Software (OSS) containing:-

uClinux Operating System (a streamlined variant of Linux OS)
RTP (RFC 3550) Real-Time Transport Protocol Media Library
RTSP (RFC 2326) Real-Time Streaming Protocol Media Support
SIP (RFC 3261) Session Initiation Protocol Voice over IP Stack
User-mode "glue" applications

Northern Hi-Tec
Wasco House
Willow Lane
Lancaster
LA1 5NA
Tel: 01524 67833
Fax: 01524 67544
Email: sales@nht.co.uk