Net-2000™ Voice Codec Unit

Net-2000™ Voice Codec Units

The Net-2000™ VCU is available in six models, each equipped with one of DVSI's patented vocoder technologies. By incorporating DVSI vocoder software with Ethernet network connectivity the Net-2000™ VCU is ideal for OEM digital-communication applications, including Voice Over Internet Protocol (VoIP), wireless telephony and voice-monitoring / recording products.

Proven Technology at rates from 2.0 to 9.6 kbps


The Net-2000™ Voice Codec Unit (VCU) represents the latest advancement in voice compression technology offered by Digital Voice Systems, Inc. (DVSI). The Net-2000™ VCU hardware incorporates DVSI's patented vocoder software for voice compression applications geared toward Ethernet-based and wireless communication systems. The Net-2000™ VCU is designed for flexibility in integration, making it well-suited for a variety of other OEM digital-communication applications, including Voice Over Internet Protocol (VoIP), wireless telephony and voice-monitoring / recording products.

All Net-2000™ VCU models integrate an UDP/IP packet protocol for remote access and control. The 10Base-T Ethernet connection on the Net-2000™ VCU allows full-duplex real-time or half-duplex non-real-time voice compression applications over a Local Area Network (LAN). Using the LAN, two Net-2000™VCUs (of the same models) can communicate to create a Voice Over Internet Protocol (VOIP) Ethernet-based vocoder communication system. Communicating between two Net-2000™ VCUs is as easy as entering the IP address (or host name) of the Net-2000™ VCU units, selecting the desired voice interface and the Full-Rate or Half-Rate Vocoder mode.

Net-2000 Block Diagram

When two Net-2000™VCUs communicate, each converts the input analog speech into digital speech samples, encodes the speech using the selected vocoder rate and sends the compressed bit stream out as UDP/IP packets over the Ethernet interface. Simultaneously, the compressed bit stream of UDP packets from the other Net-2000™ VCU are read from the Ethernet interface and decoded back into digital speech samples. The decoded samples are converted back into analog speech via the AIC-10 codec whose output is sent to both the handset and line-level output connections. Since the channel data is a packet-based UDP Ethernet protocol, users can develop their own customized controls and user interfaces so that the Net-2000™ VCU can fit into an endless array of applications.

Digital Connectivity

The UDP/IP connection can also be used to encode/decode files from a PC, or other UDP/IP device making the Net-2000™ VCU ideal for compressed-voice storage applications or non-real-time testing. Alternatively, the Net-2000™ VCU can loop back the VOIP digital data to itself for voice monitoring and evaluation applications.

The Ethernet connection to a LAN provides the ability for any PC on the network to use a standard web browser to control the Net-2000™ VCU. The user-friendly web server built into each model of the Net-2000™ makes it easy to select analog audio I/O interfaces, select the vocoder mode and to establish communication across the UDP/IP Ethernet connection. In addition to the control, the web pages display information about network settings, operating mode and system status. Since the Net-2000™ uses Ethernet, its web page can even be accessed from notebook or tablet PC via wireless network.

Several Interfaces Provide Flexibility

To meet a wide range of communication system requirements, the Net-2000™ Voice Codec Unit hosts a variety of inputs and outputs. For uncompressed analog voice I/O, the Net-2000™ VCU supports 4-wire and handset analog interfaces. For compressed voice-data communication across a channel, digitized speech can be transmitted and received through the UDP/IP packet interface. A unique feature of the Net-2000™ VCU is that the compress voice channel data and the uncompressed voice can be transmitted over Ethernet using the same UDP/IP packet interface.

Fast and Easy Set Up

Initial set up of the Net-2000™ VCU is fast and straightforward thanks to its Ethernet network connection. It is equipped to handle IP address information from a DHCP server when available on the LAN. Alternatively, the Net-2000™ VCU's RS-232 serial port can be used as a console terminal to allow low-level network set-up and selection among the various input and output audio interfaces.

DVSI developed the Net-2000™ VCU to package the latest software into a hardware platform that does not require licensing fees or royalties. With off-the-shelf availability, the Net-2000™ VCU provides cost effective voice compression without the risks and engineering expenses associated with new product development.

Features Stand-alone Design

  • UDP/IP-enabled voice codec unit interfaces DVSI vocoder technology with Analog I/O and digital networks
  • Real-time, full-duplex communications to digital devices or other Net-2000™ units via UDP/IP packet protocol interface
  • Both digital voice and compressed voice channel data can be transmitted over the same UDP/IP packet interface
  • Encode/Decode files stored on a PC or networked attached storage

Flexibility and Performance

  • High-performance, line-level audio using 16-bit linear codec
  • 4-wire analog input/outputs
  • Built-in web server for set-up and control from a PC on the LAN

Easy to Integrate and Operate

  • The RS-232 serial port can be used as a console terminal for system set up and control
  • Easy network set up with built-in DHCP to handle IP address information when available on LAN
  • The embedded operation software can be field upgradeable
  • Rack-mountable aluminum chassis design

Net-2000™ VCU Available software implementations

Models Description
Net-2000™ P-25 The Net-2000™ P25 VCU incorporates both the full-rate (7.2 kbps) and half-rate (3.6 kbps) APCO Project 25 vocoders.
Net-2000™ AMBE® The Net-2000™ AMBE® VCU incorporates DVSI's AMBE®, AMBE+™ and AMBE+2™ vocoders at various data rates.
Net-2000™ GMR-1 The Net-2000™ GMR-1 VCU incorporates the ETSI - Thuraya vocoder (5200 bps).
Net-2000™ GMR-2 The Net-2000™ GMR-2 VCU incorporates the ETSI - ACeS vocoder (3600 bps).
Net-2000™ GMR2+ The Net-2000™ GMR2+ VCU incorporates the GMR2+ 6000 bps vocoder (including FEC).
Net-2000™ BGAN The Net-2000™ BGAN VCU contains an implementation of Inmarsat’s BGAN 4 kbps vocoder.

Specifications (same for all models)

Rear Panel Connections Connector
Serial Port DB9s
RS-422 Synchronous DB-15HD
RS-422 Asynchronous RJ-45
2 Wire I/O RJ-11
Analog Line In RCA Jack
Analog Line Out RCA Jack
Handset RJ-14
AC Line In Power Cord Receptacle

Technical Specifications
Power: V 100 - 240 V ~
FR 50 / 60 Hz
Mechanical Size: (W x H x D) 17.25 X 3.5 X  7.25 inch 
Weight: 4.5 pounds