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T1/E1 FIBEROPTIC LINE DRIVER
2. Introduction
2.1 Functional Description
The T1/E1 Fiberoptic Line Driver is used for transmission of T1 (1.544 Mbps) and
E1 (2.048 Mbps) data over multi-mode or single-mode fiberoptic media. The Line
Driver is transparent to T1 and E1 framing, and can transmit data using any
framing pattern with AMI, HDB3 or B8ZS coded signals.
The Line Driver converts the T1/E1 electrical signal into an optical signal using
an infrared LED transmitter. At the opposite end of the fiber, the optical signal is
converted back into an electrical signal and amplified to the required level.
Automatic Gain Control (AGC) circuits are used to accommodate various
distances. The Line Driver uses a Phase Locked Loop (PLL) circuit to recover data
and clock from the signal. The Line Driver provides three user-selectable electrical
interface options:
• T1—for 100 terminated balanced signals
• E1—for 120 terminated balanced signals
• E1—for 75 terminated unbalanced signals
Both a 15-pin connector and coaxial connectors are provided on the rear panel.
Internal jumpers enable the input/output ports to be grounded or floating,
according to the application.
Diagnostic and alarm features include an LED status indicator, all “ones”
signaling (AIS) alarm generation, and dry contact closure upon link failure.
The Line Driver is designed to operate with several different grades and sizes
of fiberoptic cable, and provides the user with:
• Immunity to electrical interference such as EMI, RFI, spikes and differential
ground loops.
• Protection from sparking and lightning.
• A secure link in hazardous or hostile environments.
The standard version is supplied with an 850-nm multi-mode fiberoptic
interface. A 1300 nm single- or multi-mode interface is also available.
