Thiết Bi Chuyển Đổi Quang Điên Stm-1 (Stm-1 O/E Converter)

STM-1 O/E CONVERTER

1.   Introduction

The STM-1 O/E Converter is designed to provide one converter between electrical interface and optical interface of STM-1 signal. The converter features compactness, light weight, low power consumtion and high reliability.

The STM-1 O/E Converter operates on 1.3 µm lasers, with a typical transmission distance of 40 km over single mode optical fibers. For longer hops, 1.55µm laser sources may be selected.

Exterior power supply, all the functional blocks are integrated on a single PC boad, which makes the modem compact and reliable. 220 VAC or -48VDC power options are available by selecting an appropriate plug-in power unit.

The converter enclosure is a standard half 19” wide 1U metal box, suitable for rack mounting, or as a desk top unit.

2.   Typical application

The STM-1 O/E Converter provides one converter between electrical interface and optical interface of STM-1 (155.520Mbit/s) signal of SDH or ATM network. The

3.   Panel arrangement

3.1Front panel arrangement

There are green, red and yellow LEDs on the front panel of the STM-1 O/E Converter. The following table lists meaning of all the LEDs and possible causes.

Table 1. LED descriptions:

There are 4 DIP switch in the front panel. They are used to set working mode of converter. The following tables lists 4 DIP switches description.

Table 2. 4 DIP switches description.

Table 3. Working modes description 

3.2  Rear panel arrangement

There are STM-1 optical interfaces, STM-1 electrical interfaces, power switch and power in port in Rear panel.

There are two types of the STM-1 O/E Converter, 220VAC and -48VDC, according to the power supply.

For STM-1 O/E Converter, the STM-1 electrical interface is BNC sockets, “IN” is incoming STM-1 electrical signal and “OUT” is outgoing STM-1 electrical signal. And the output relationship. Do not bend fiber to sharp angles to prevent damage. Do not look directly into the fiber end or the Tx connector socket for extended time; it may be harmful to the eyes.

Loop backs.

The STM-1 O/E Converter support panel DIPs switch control of loop backs to allow for installation and maintenance checks.

4.      Installation

4.1  Electrical

4.1.1        Power connection

Plug-in power unit is installed inside the power chamber. Two types of power units are available, 220VAC, or -48VDC.

When AC unit is installed, the power inlet, a fuse, and a switch are integrated with the unit, as shown in the diagram below.

Use the power cord supplied with the STM-1 O/E Converter. Plug in the power cord to the ac power inlet at the back of the power chamber. Be sure to use a wall outlet with correct voltage and a secure earth connection.

When -48VDC power is selected, a cover plate is fixed on the chamber by screws, -48VDC power connector is on the right side of the power chamber. Connect to -48V power source using a pair of wires about 1mm in diameter to the power-in connector. Remove about 10mm of the protective insulator from the wire end. Prepare the wire end with solder. Push inward the yellow release lever on top of the connector with a screw driver, plug the prepared wire end well into the hole, then release the push.

4.1.2        STM-1 electrical connections

There are BNC sockets for 75 Ω coaxial STM-1 electrical interface for converter.

4.1.3        STM-1 fiber connection

Use SC or FC type connectors to connect the STM-1 O/E Converter to the transmission cable. Pay attention to the input and output relationship. Do not bend fiber to shrp angles to prevent damage. Do not look directly into the fiber end or the Tx connector socket for extended time, it may be harmful to the eyes.

5.      Operation and maintenance.

When all the connections are down, switch on the Converter. Observe all the alarm LED’s for any possible installation errors. Check the output optical power using an optical power meter. The reading should be within specification.

Mesure the optical power at the receiver end. Make sure that the power level is between the maximum allowable input power and sensitivity given in the specification. It is preferred to leave a margin of few dB’s for stable operation.

6.      Specifications

6.1  Capacity : one STM-1 O/E converter.

6.2  STM-1 Optical interface.

ITU-T G.957 STM-1

Line rate: 155520kbps

Line code: Scrambled NRZ

Wavelength: 1.31 µm (typical)  1.55 µm (optional)