10
T3 FIBER OPTIC LINE DRIVER
2. Introduction
2.1 Overview
The T3 Fiber Optic Line Drivers are fiberoptic modems for transmission of T3
(44.736 Mbps) over multimode or single-mode fiberoptic media. The line drivers
are transparent to framing and can transmit data using any framing pattern with
B3ZS coded signals.
Conversion of the electrical signal into an optical signal is achieved using an
infrared light-emitting diode. At the opposite end of the fiber, the optical signal is
converted back into an electrical signal and amplified to the required level.
The T3 Fiber Optic Line Drivers use a Phase Locked Loop (PLL) circuit electrical
interface (on BNC connectors with 75
Ω
impedance) to recover data and clock
from the signal.
Diagnostic and alarm features include LED status indicators, V.54 loopback
activated from the front panel, and supervisory port for reporting system status.
2.1.1 V
ERSIONS
Two versions are available:
• T3 Fiber Optic Line Driver ST, 1310-nm Single-Mode (MT618A-ST-R2)
• T3 Fiber Optic Line Driver ST, 850-nm Multimode (MT619A-ST-R2)
2.1.2 A
PPLICATION
In the application shown in Figure 2-1, each line driver receives T3 signals, which
are equalized to overcome electrical link distortion. The line driver converts the T3
signal into an optical signal.
Figure 2-1. Typical application.
Fiber Optic
FOM-T3/E3
Coax
Coax
FOM-T3/E3
T3 or E3
T3 or E3
T3/E3
MUX
T3/E3
MUX
Up to 68.35
miles (110 km)
T3 Mux
T3 Mux
Line
Driver
Line
Driver
T3
T3
