1. Introduction
1.1 General Description
The E1 Plus fiber optic converter (LE-820M/1E1 Plus and LE-1300S/1E1 Plus)
products from LaserBit Communications offer cost effective and highly reliable
solution for connecting equipment with ITU-T G.703 (E1) interface to optical
networks. The converters give fully transparent connection both for structured or
unstructured signals at E1 (2.048 Mbps) level. The devices are designed to be
extremely flexible yet easy to use. The copper line interface is configurable both
for balanced (UTP) and unbalanced (COAX) connection. Copper and fiber loop
back modes provide useful help in troubleshooting. The loop back modes also
can be turned on and monitored remotely. Color LED indicators provide
extended status and alarm reporting. The selectable line coding and AIS
handling gives further flexibility when integrating the equipment into an existing
system. The E1 Plus models are equipped with Service Channel feature, which
transmits one voice channel, one RS-232 channel and 2 x 24 low speed signal
bits on top of the data stream. This solution makes the equipment ideal for
applications where alarm and status monitoring or remote management of other
equipment is required. Besides the AC Power Supply, the devices can be
ordered with 48 VDC PSU for Telco applications.
1.2 Theory of operation
The basic function of the E1 Plus converter is to transmit and receive E1 signal
over fiber optic networks. In addition to that, the equipment is capable of
transmitting auxiliary service data on top of the standard E1 data stream. The
two functions are realized by two independent functional units inside the device
as it is shown on Figure 1 below.
A – RS-232 serial, duplex, up to 38.400 kbps
B – Analogue voice channel, 16 kbps ADPCM
C – Low speed alarm and control signals, 2 x 24
E1
Fiber optic link
E1SC-MM
SC-UIM
E1SC-MM
SC-UIM
E1
A
B
C
A
B
C
