FOCAL 903 Basics

FOCAL 903 Basics

Before i teach you troubleshooting its important to learn some basics about this wonderful unit.

SO there are two units Surface and Subsea at first i will talk about surface unit only and later on about subsea unit.

High Speed and Medium Speed unit 

There are two types of surface units available one is High speed and another is Medium speed unit,The only difference between the two is number of data and Video channels available in a unit.

As Shown in figure is a medium speed unit and has 8 data channels and 4 video channels while the high speed unit has 16 data channels and 8 video channels,Mostly in Vehicle is a high speed unit and for cage or TMS is a medium speed unit due to less number of camera's and equipments.

Now in Medium speed unit there are 2 backplanes also known as AIB (Adaptable interface board) 1 AIB has 4 data channels slots to place daughter cards in it, One backplane is dedicated to RS-232 and cannot be configured for any other protocol.So we have 4 RS-232 data channels

The second backplane also has daughter card slots,User can place any daughter card according to requirement e.g. RS422/485, Arcnet or even RS-232.

While in High speed unit there are 4 backplanes out of which 2 backplanes are dedicated for RS-232 and other 2 backplanes can be configured for any other protocol according to requirement.Please refer to fig below to see which backplanes are dedicated for RS-232.

Now we have learned some basics about Surface unit let's talk about subsea,Subsea units are also referred as HD (High Density) units as well because of shortage of space subsea units are compact and smaller in size so they can be fit in POD.The difference of High and medium speed and allotment of AIB backplanes are same as it was in Surface units.

Operation of FOCAL 903

As One of the biggest advantage of Focal 903 is a backup fiber and Diagnostic port that gives the real time monitoring of Fiber loss,These is a separate post on how to use diagnostic port.

So lets talk about back up fiber as there is a selector switch to select between Fiber 1 or Fiber 2 or leave it on automatic mode and fiber with minimum loss will be selected.(See post Loss in a FO).

Always remember when you do bench test for these units it is recommended to have minimum 5dB of loss between surface and Subsea unit.

The maximum loss between Surface and Subsea Unit can be around 20dB,For more information on losses please refer to blog post Loss in a FO.

In my next post i will write about Troubleshooting Focal 903.