Net-2000™ Single Channel Voice Codec Unit

Net-2000™ Single Channel Voice Codec Units

The Net-2000™ VCU is available in six models, each equipped with one of DVSI's patented vocoder technology. By incorporating DVSI vocoder software with Ethernet network connectivity the Net-2000™ VCU is ideal for single voice channel 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™ Single Channel 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 single channel 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 single channel 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™ Single Channel 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 single channel 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

  • Real-time, full-duplex single channel communications to digital devices or other Net-2000™ units via UDP/IP packet protocol interface
  • UDP/IP-enabled voice codec unit interfaces DVSI vocoder technology with Analog I/O and digital networks
  • 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
Voice Channel Capacity: One
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