E-carrier System: E0, E1, E2, E3, E4 Explained

Introduction

E-Carrier System is developed to transmit multiple voice calls and data streams using TDM (Time Division Multiplexing). This digital transmission hierarchy has been initially used in Europe. This system has several levels from E0 to E4, each supporting different data rates and channels.

The E-carrier system (Ethernet carrier) comprises E0, E1, E2, E3, and E4. It’s often referred to as a non-synchronous PDH (Plesiochronous Digital Hierarchy).

E-Carrier hierarchy

Here’s a breakdown:

E0: This is the base level which has capacity to carry single voice channel having rate of 64 kbps.

E1: It comprises 32 number of E0 channels with support for total capacity of 2.048 Mbps. In E1 system, 30 channels are used for voice or data and remaining two are used for framing and signaling.

E2: This system multiplexes four number of E1 lines and support total capacity of 8.448 Mbps.

E3: This system combines four number of E2 lines with total data rate of 34.368 Mbps.

E4: This system aggregates four number of E3 lines and delivers total data rate of 139.264 Mbps.

Summary

Each ascending level in E-carrier hierarchy multiplexes multiple lower level channels. This facilitates scalable and efficient voice/data transmission across telecom networks. This structure has been used across various regions, particularly outside Japan and North America region.​