Configuring Digital Voice Subscriber Lines; Introduction To E1 And T1; Overview; E1 And T1 Voice Functions - HP FlexNetwork MSR Series Configuration Manual

Configuring digital voice subscriber lines

This chapter covers the configuration of E1, T1, and BSV voice subscriber lines.

Introduction to E1 and T1

Overview

Plesiochronous digital hierarchy (PDH) includes two major communications systems: ITU-T E1
system and ANSI T1 system. The E1 system is dominant in Europe. The T1 system is dominant in
USA, Canada and Japan.
E1 and T1 use the same sampling frequency (8 kHz), PCM frame length (125 μs), bits per code word
(8 bits) and timeslot bit rate (64 kbps). They differ in these aspects:
•
E1 adopts A law coding/decoding of 13-segment but T1 adopts μ law coding/decoding of
15-segment.
•
Each PCM primary frame of E1 contains 32 timeslots but that of T1 contains 24 timeslots. Each
PCM primary frame of E1 contains 256 bits but that of T1 contains 193 bits. Therefore, E1
provides 2.048 Mbps bandwidth and T1 provides 1.544 Mbps bandwidth.

E1 and T1 voice functions

E1 and T1 mainly provide voice and signaling trunks to the PSTN. To realize this function, the router
must have E1 and T1 voice interfaces and be configured with functions required for transmitting
voice over E1 and T1 lines.
The E1 and T1 voice physical interfaces are VE1 and VT1 interfaces, respectively.
PSTN and routers are connected through E1/T1 trunks, as shown in
Figure 17 Network diagram
E1/T1 voice transmission allows a router to provide more channels of voice communication, greatly
improving router utilization and broadening service range.

E1 and T1 interfaces

This section covers information related to E1 and T1 interfaces.
E1 interface
An E1 interface is logically divided into timeslots (TSs) with TS 16 being a signaling channel.
On E1 interfaces, you can create PRI groups or TS sets.
60
Figure 17.