Chapter 1 - Introduction HCD-E1
Installation & Operation Manual
1-16 Functional Description 01/01/01 08:07
Figure 1-8 Sublink Timing, Flow of Timing Signals in a Typical Application
Main Principles ofOperation
This section describes the E1 and the HDSL environments, to provide the
background information required for the understanding of the configuration
parameters of the HCD-E1 system.
The E1 (CEPT) Environment
The E1 line interfaces of the HCD-E1 comply with the applicable
requirements of ITU-T Rec. G.703, G.704, G.706, G.732, and G.823.

E1 Signal Structure

The E1 line operates at a nominal rate of 2.048 Mbps, using a line signal
encoded according to the High-Density Bipolar 3 (HDB3) code. The data
transferred over the E1 line is organized in frames. Each E1 frame includes
256 bits. The E1 frame format is shown in Figure 1-9.