Stereo Multi-Connection Codec


APT IP/ISDN CODEC (formerly known as WorldCast Equinox) is a multi-algorithm, fully duplex, stereo audio codec offering IP, ISDN and X.21 / V.35 connections.

Designed primarily for studio to transmitter links and interstudio networking applications, the APT IP/ISDN CODEC provides a reliable platform for the transport of broadcast grade audio with 24/7/365 reliability.


Audemat ScriptEasy Powerful Performance

  • Fully duplex stereo audio codec
  • High quality audio transport over IP networks with support for Unicast & Multicast applications
  • ISDN interface with Mucas Bonding & L3 Telos Bonding, CCS, H221 & Hitachi ISDN Bonding
  • X.21/V.35 interface
  • Robust DSP-based platform for mission-critical operation


Audemat ScriptEasy Powerful Control

  • Front panel operation with level meters and headphone socket
  • Highly intuitive Network Management Software (NMS)
  • Allows management of network conditions such as packet size, buffers and QoS levels for optimum audio performance
  • Embedded Auxiliary data for transmission of RBDS /RDS or PAD


Audemat ScriptEasy Powerful Savings

  • Competitvely-priced professional audio codec
  • Flexible Platform can be deployed on many different networks
  • Support for cost-effective IP networking


  • Automatic back-up from IP to X.21/V.35 or ISDN - or from X.21/V.35 to IP or ISDN
  • Non-destructive, cascade-resilient, real-time coding with aptX® Enhanced
  • Wide range of algorithm and coding options 
  • Support for SIP/SDP
  • Support for Layer III bonding ensuring ISDN compatibility with existing units
  • DSP-based platform for 24/7/365 reliability
  • Reliable DSP-based architecture


Offering multiple connection options, the IP/ISDN codec is ideal for use by broadcasters who wish to back-up their primary IP connection with a secondary ISDN or X.21 / V.35 link. The inbuilt silence detection will identify a failure on the main link and automatically switch to the pre-defined back-up connection.

APT IP/ISDN to APT IP/ISDN duplex IP link with X21 or ISDN Backup connection
user report

User report

"We believe that APT codecs offer a unique combination of great audio quality with a very high level of reliability and this has ensured that they have become a preferred supplier amongst Japanese broadcasters"
Suzuki San, Sales Manager, TechnoHouse Inc, Japan


Current version: 3.3


IPEthernet 1 x RJ45, RTP/UDP, SIP/ SDP
X.21 / V.3515 Way D Type DTE, RS422 levels, Rates 64-576 kbps
ISDN2x RJ45 - standard
Aux Data9 pin D Type, RS232 level
Data Rates (embedded)1200, 2400,4800, 9600 Baud
Data Rates (via IP)1200, 2400, 4800, 9600, 19200 Baud
ControlNMS Software & SNMP, Optional front panel
Digital Audio I/OAES/EBU, Balanced XLR-3, Impedance 110 Ω
Digital Ref InputAES-3
Analog Audio I/OBalanced XLR-3, Input Impedance >10k / 600 Ω, Output Impedance <50 / 600 Ω
Alarms8 Alarms on 25 pin D Type, NO/NC relay contacts
Inputs25 way D Type, 8 Opto-coupled or Switch Inputs driving 8 Relay Outputs
Digital Operation10Hz through to 22.5kHz mono & stereo
Digital Audio Bandwith10Hz through to 22.5kHz mono & stereo
ADC / DAC Sampling Rates8kHz-48kHz
Analog Audio Bandwith10Hz through to 22.5kHz mono & stereo
Sample Rate Converter 8:1 (with bypass modes)
A/D Converter 24-bit/96kHz sigma-delta
Standard CodingLinear PCM 16 / 20 / 24Bit (Dolby E support), aptX Enhanced 16-Bit & 24-Bit, MPEG I Layer II, MPEG I Layer III, MPEG 2 Layer II, G.711, G.722, ISO/MPEG 2/4 AAC-LC, ISO/MPEG4 AAC-LD & AAC-ELD, HE-AAC v2
Compression RatioEnhanced apt-X:   4:1 / others: Variable
Coding DelayEnhanced apt-X 1.9ms @48kHz Fs
Dynamic Range16 Bit > 85dB,  24 Bit > 120dB
Phase Response Linear0 to Fs/2
Pass Band Ripple< 0.2dB
Physical specification
External Dimensions (W / L / H)44mm x 480mm x 360mm  / 1.75” x 19” x 14.2”
Weight3.5Kg / 7.7lbs
Main Power Supply100-250VAC, 50-60Hz (optional 48VDC Supply)
Power Consumption< 20W
Guaranteed Working Temperatures0°C - +55°C
Humidity10-95% non-condensing relative humidity



  • APT IP/ISDN CODEC - Manual (Legacy product)

    Published on Jun 3, 2020

Tech Notes

  • The Essential Guide To Audio Over IP for Broadcasters

    Published on May 29, 2020


  • WorldNet NMS Software

    Published on Nov 5, 2018


  • Conformity certificate - APT IP ISDN CODEC

    Published on May 12, 2020


  • WorldCast Systems Overview

    Published on Oct 1, 2019

Quick Start Guides

  • APT IP/ISDN CODEC - Quick start

    Published on May 13, 2020

Press Kit

  • WorldCast Systems Logo - Press Kit

    Published on Sep 16, 2019