V-FAST Intermediate Range Fibre Optic Link

The Nebula Manufacturing Inc. V-FASTA is a 1300nm (V-FASTB 1550nm) 10 or 100 megabit Ethernet bridge that supervises the fibre link in both directions. After two-way fibre integrity is established the ALARM led goes off and the twisted pair ports are turned on, signaling to the attached equipment communication can begin.

V-FAST Interface

 

Two FC/PC optical connectors (TX and RX)

 

Laser cut off switch

 

Two RJ45 Twisted pair ports (2nd port is optioned for priority traffic i.e. voice or video)

LED Indicators

 

PWR

Power

 

LASER

Laser on

 

ALARM

Fibre problem

 

Unlabelled

Future option

 

F DUP

Full duplex

 

FLK

Fibre link detected

 

CLN

Collision

 

ACT

Twisted pair activity

 

TLK

Port one link pulses detected

 

TLK

Port two link pulses detected

 

FAST

100 megabit operation

Link Budget

 

V-FAST transmit level is -4 dBm and receive level is –34 dBm yields a link budget of 30 dB (approximately 60 km depending on fiber loss)

 

V-FASTA transmit level is –7 dBm and receive level is –32 dBm yields a link budget of 25 dB (approximately 50 km)

 

V_FASTB transmit level is –7 dBm and receive level is –33 dBm yields a link budget of 26 dB (approximately 50 km)

 

 

Receiver overload better than –3 dBm (0 dBm typical)

 

Receiver optical damage greater than +3 dBm

Power

 

Designed for redundant powering from 48 or 12 volt DC. Power consumption is 7 watts.

Dipswitch Option Settings

 

Position

Name

Function when on

 

One

FAST

100 megabit operation

 

Two

F DUP

full duplex operation

 

Three

CO

override; increases interpacket gap for premises connected
equipment when not powered by a 48 volt power source

 

Four

OP 1

option one; duplicates traffic on both ports

 

Five

OP 2

option two; traffic shaping option

 

Six

OP 3

option three; traffic shaping option

Factory Shipped Option Setting

 

All switches set to off; 10 megabit half duplex operation